&

4th International Conference on Fluid Flow,
Heat and Mass Transfer (FFHMT'17)
&
International Conference of
Energy Harvesting, Storage, and Transfer (EHST'17)


August 21 - 23, 2017 | Toronto, Canada

Program

The organizing committees of the two co-located events, FFHMT'17 and EHST'17, have decided to allow registrants of either conference to attend sessions from both events. As a result, we encourage attendees to study the program and attend the sessions which they may find relevant/interesting.

The Conferences will be held at Ryerson University in the The George Vari Engineering and Computing Centre. Please click here for map of the location.



Monday
August 21


3:00 PM - 5:00 PM
Registrations
Registrations will be taking place in the hall next to room ENG-LG-015.

Tuesday
August 22


8:00 AM - 9:00 AM
Registrations
Registrations will be taking place in the hall next to room ENG-LG-015.
Room: ENG-LG-006
Room: ENG-LG-013
9:00 AM - 9:15 AM
Official Opening
Dr. Boguslaw Kruczek, University of Ottawa, Canada
- -
9:15 AM - 10:00 AM
Keynote Lecture
Novel High Performance Lubricants for Industrial and Biomedical Applications
Dr. Dana Grecov, University of British Columbia, Canada
- -
10:00 AM - 10:45 AM
Keynote Lecture
Power-to-Gas Pathways to a Fossil Free Energy System
Dr. Michael Fowler, University of Waterloo, Canada
- -
10:45 AM - 11:05 AM
Coffee Break
11:05 AM - 12:05 PM
Session
CFD I
11:05 AM - 12:05 PM
Session
Energy Storage
12:05 PM - 12:10 PM
Group Photo - Please come to the registration desk to take the photo.
12:10 PM - 1:05 PM
Lunch
1:05 PM - 3:15 PM
Session
CFD II
1:05 PM - 3:10 PM
Session
Fluid Flow, Heat and Mass Transfer Equipment
3:15 PM - 3:35
Coffee Break
3:35 PM - 5:55 PM
Session
CFD III
3:35 PM - 4:55 PM
Session
Transport Phenomena in Porous Media

Keynote Lecture

9:15 AM - 10:00 AM | Room: ENG-LG-006 | Session Chair: Dr. Boguslaw Kruczek, University of Ottawa, Canada

Novel High Performance Lubricants for Industrial and Biomedical Applications
Dr. Dana Grecov, University of British Columbia, Canada


Abstract
The development of a new generation of lubricants is of paramount technological and economic relevance as it is estimated that half of our energy consumption is dissipated as friction.
Liquid Crystals (LCs) are anisotropic viscoelastic materials; the combination of fluid-like flow with crystal-like anisotropy makes its phases interesting as modifiers of interfacial behavior when applied as lubricants. The anisotropy of the viscosity coefficient, with respect to different flow directions, is a unique property of the liquid crystalline phase. The ability of liquid crystalline materials to form ordered boundary layers with good load-carrying capacity, and to lower the friction coefficients, wear rates and contact temperatures of sliding surfaces, thus contributing to increase the components service life and save energy has been widely demonstrated. Due to the bio-compatible nature of most lyotropic liquid crystalline materials, they have been considered as viable candidates to be used as bio-lubricants.
The computational modeling and experiments offer an efficient pathway to formulate novel lubricants which are economically viable. To improve lubrication efficiency we aim to develop a model of lubrication flow using liquid crystals or nanoparticles as additives that is experimentally validated and can be implemented into modern computational engineering and design tools.

Keynote Lecture

10:00 AM - 10:45 AM | Room: ENG-LG-006 | Session Chair: Dr. Boguslaw Kruczek, University of Ottawa, Canada

Power-to-Gas Pathways to a Fossil Free Energy System
Dr. Michael Fowler, University of Waterloo, Canada


Abstract
Power-to-gas is a novel energy storage concept that can help in providing energy storage and offer a sustainable and efficient alternative ways utilize the surplus electricity generated by the provincial grid of Ontario, Canada. The ability of the power to gas energy hubs to utilize the existing natural gas distribution and storage network (within the province) to distribute and store the electrolytic hydrogen produced is one of its major advantages. There a number of different 'pathway' for using the hydrogen generated via the Power-to-Gas concept, and this presentation will outline the pathways for use of the hydrogen and for the provision of energy storage. Also an optimization model of a power to gas energy hub having a hydrogen production module capacity of 2 MW has been developed and will be presented. The goal of this optimization study was to carry out an economic feasibility of the energy hub under existing pricing mechanisms for the three primary services that it provides, namely: 1) Offsetting CO2 emissions at natural gas end users by providing hydrogen enriched natural gas; 2) Providing demand response when directed by the Independent Electricity System Operator of the province, and 3) Providing pure hydrogen to a fuel cell vehicle refueling station.

Session

11:05 AM - 12:05 PM | Room: ENG-LG-006

CFD I
Session Chair: Dr. Dana Grecov, University of British Columbia, Canada


Time
11:05 - 11:15
Authors
Haoyu Wu, Boguslaw Kruczek, Jules Thibault
Time
11:15 - 11:35
Authors
Nhut Tran-Minh, Frank Karlsen, Bendik Fyhn Terjesen
Abstract
This paper presents the design of continuous sorting and concentration unit that can be used for particles or cells in the large volume of sea, waste, or fresh water. With the optimized profile of ellipse in combination with array of shield-like micropillars, efficiency of continuous sorting and concentration unit was examined by theoretical methods including Finite Element Method (FEM). With software (COMSOL 5.2) for computational fluid dynamics (CFD), we simulated unit in a laminar flow regime. Numerical results illustrate that the high velocity region which can be obtained along two side of unit and the penetration channels.
Keywords
Computational fluid dynamics, sorting, concentration, micropillar
Time
11:35 - 11:45
Authors
U. I. Mohd Ali, A. Zamiri, S. Y. Lee, J. T. Chung
Time
11:45 - 11:55
Authors
Dragan Mandic
Abstract
The subject of this paper is modeling of fluid flow and heat transfer in channels of plate heat exchangers for heating domestic hot water heating substation in Belgrade. Of particular importance is that in this paper modeling hydraulic parameters of fluid flow and heat transfer parameters made in the collective and individual channels plate heat exchangers. Geometric model of collective channel plate for the passage of fluid is obtained by connecting all geometrical model of individual channels on one plate exchanger. On both geometric models are separately generated numerical network, and the boundary conditions of fluid flow parameters of the budget adopted different mass flow rates of fluids through them. The uneven distribution of shear stresses on the walls of plate exchanger is determined at various speeds of fluid in the collective and individual channels for the fluids flow. At the same time the rate of flow in the channels had cumulative value of 0.1m / sec, and in individual channels amounted to 0.01m / sec. Intensities specified shear stresses obtained CFD modeling are compared with experimental results of these stress obtained from the measurement of process parameters of fluid flow, and at approximately the same velocity (0.1m / sec). Because of the significant impact the distribution and intensity of tangential stress on the plate fouling heat exchanger, results can serve as a basis for determining the new project of procedures plate heat exchangers in district heating systems.
Keywords
Plate heat exchangers, fluid flow, chanells
Time
11:55 - 12:05
Authors
Ramtin Barzegarian, Tooraj Yousefi, Alireza Aloueyan

Session

11:05 AM - 12:05 PM | Room: ENG-LG-013

Energy Storage
Session Chair: Dr. Michael Fowler, University of Waterloo, Canada


Time
11:05 - 11:15
Authors
Nima Talebzadeh, Paul G. O’Brien
Time
11:15 - 11:25
Authors
Ajaykrishna Ramasubramanian, Vitaliy Yurkiv, Ali Najafi, Ali Khounsay, Reza Shahbazian-Yassar, Farzad Mashayek
Time
11:25 - 11:45
Authors
Pranay Shrestha, Rupak Banerjee, Jongmin Lee, Aimy Bazylak
Abstract
Polymer electrolyte membrane (PEM) fuel cells are energy conversion devices that are promising components of a sustainable energy system. However, conventional fuel cells suffer from performance degradation at low humidification. To address poor performance under low humidity conditions, we investigate the effect of custom hydrophilic microporous layer (MPL) coatings on liquid water distributions in gas diffusion layers (GDLs), observed in operando using X-ray synchrotron radiography. The visualization was performed during low humidity operating conditions at 60°C, with inlet gas relative humidity (RH) of 50%. Hydrophilic MPLs were coated onto commercial hydrophobic GDLs, and electrical output and simultaneous liquid water measurements were measured, using a fuel cell test station and X-ray synchrotron radiography respectively. The hydrophilic materials showed lower values of membrane resistance (quantified by high frequency resistance) compared to the benchmark hydrophobic GDL. The relatively lower membrane resistance was attributed to improved membrane hydration under low humidity conditions. Correspondingly, the catalyst layer (CL)-MPL interface contained larger quantities of liquid water with the addition of the hydrophilic coating. However, excess liquid water at the cathode side of the GDL led to high oxygen mass transport losses at high current densities. Understanding gained from this study can be used to optimize wettability of the MPL to operate the fuel cell at low or no external humidification.
Keywords
PEM Fuel Cells, Hydrophilic Microporous Layer, Liquid Water Visualization, Low Humidity
Time
11:45 - 12:05
Authors
Marek Borowiec, Arkadiusz Syta, Grzegorz Litak
Abstract
In the paper the magnetostrictive (MsM) cantilever beam model was analysed. The MsM material was taken into account as Galfenol, the alloy including the Gallium and the Ferrum. The burdened beam system via external excitation produces the magnetic field due to created maximal stress on the external beam fibres. By applied the external coil subsystem, the electrical energy was captured. The main goal of the analysis was to investigate the influence of the beam neutral axis position for energy harvesting efficiency. In case, the neutral axis agrees with the symmetry axis of the magnetostrictive beam, the magnetic fields cancel each other out, while stress is on. This effect disappears while the neutral axis is moved beyond the MsM beam's symmetry. It was estimated the influence of the beam response vibration amplitude on the output electric energy extracted from the system, at increased an effective MsM layer. It was analysed in the vicinity of the first resonance frequency, where the output voltage reached the maximum values.
Keywords
Magnetostrictive material, energy harvesting, resonance zone

Session

1:05 PM - 3:15 PM | Room: ENG-LG-006

CFD II
Session Chair: Dr. Hongyi Xu, Fudan University, China


Time
1:05 - 1:25
Authors
Masoud Darbandi, Majid Ghafourizadeh, Gerry E. Schneider
Abstract
In this work, we aim to control the emission of greenhouse gases from different syngas-fuel-based flames or the bluff-body stabilized turbulent flame. First, we validate our numerical analysis by solving a benchmark test case using the detailed-chemistry and compare our obtained results with those of experiment. The benchmark test case is fed with a syngas fuel. The comparison shows that our numerical analysis can predict the structure of benchmark flame very well. Second, we simulate the test case with fuelling the same flame; however, fed with different syngas fuels. Then, we compare their achieved greenhouse gas emissions with each other. We feed the flame with different syngas fuels produced from biomass, wood waste, and turkey feathers. Considering these different syngas fuels, we extend the scope of this study and simulate these flames under different conditions of oxidizer dilution. In other words, we dilute the oxidizer by feeding extra nitrogen and report the greenhouse gases emitted from these flames. The comparison is performed to demonstrate the effect of extra nitrogen dilution on their pollution emissions. Our findings show that the dilution of oxidizer (by feeding extra nitrogen) will considerably affect the pollutants emission form these flames. The current study also shows that the emission of carbon monoxide CO would be seriously reduced using the extra nitrogen dilution technique.
Keywords
Syngas fuel, Air pollution, Emission Control, Oxidizer dilution, CO and CO2 concentrations, Turbulent flame
Time
1:25 - 1:45
Authors
Yashar Seyed Vahedein, Alexander S. Liberson
Abstract
A modified reduced fluid-structure interaction model is derived based on expanded Hamilton’s variational principle governing the coupled incompressible viscous fluid - structure interaction (FSI) in a compliant bifurcated network. To enforce the continuity equation a Lagrange multiplier is utilized which in case of an incompressible fluid coincides with fluid pressure. The first variation of an expanded action functional yields the nonlinear governing Euler-Lagrange equations for the fully coupled nonlinear fluid – structure problem with account for fluid gravity potential. The correct boundary conditions are specified at junctions as natural boundary conditions following from the variational principle. The hyperbolic properties of derived mathematical model are analyzed and used, constructing the monotone finite volume numerical scheme, second-order accuracy in time and space. The accuracy of applied TVD (total variation diminishing) and Lax-Wendroff methods are analyzed by comparison of numerical results to the available analytical smooth and discontinuous solutions.
Keywords
Hamilton’s variational principle, incompressible viscous flow, reduced fluid-structure interaction (FSI), bifurcated arterial networks, total variation diminishing method (TVD), Lax-Wendroff methodt, break-down solution
Time
1:45 - 1:55
Authors
Yuki Tsuzuki, Emilie Roncali, Simon R. Cherry, Ralph C. Aldredge
Time
1:55 - 2:15
Authors
Tong Wang
Abstract
Flow around cylinder cascade is a common flow configuration which can be used in heat transfer and other industries. The interaction of vortices has an unavoidable impact on the downstream. The information of transient flow can be acquired by large eddy simulation(LES). In this paper, the cylinder cascade with the gap ratio of 2.0 was simulated by large eddy simulation method at two Reynolds number conditions and the mode decomposition algorithm was adopted to analyze the movement of vortex. Compared with information extracted by POD algorithm and FFT method, the validation of DMD algorithm was discussed by the results from the hypothetic scalar field and the experimental data. The accuracy of LES results and the characteristic of the vortex were analyzed by DMD algorithm. It has been verified that DMD algorithm can be used for cascade engineering on account of the accurate description of the flow structure.
Keywords
Large eddy simulation, cylinder cascade, dynamic mode decomposition, vortex structure
Time
2:15 - 2:35
Authors
Hadi Rahimi, David Buttsworth, Ray Malpress
Abstract
To achieve higher performance from ejectors at some working conditions, implementations of variable geometry might be possible. While axisymmetric ejectors with axial flow paths have limitations that make practical implementation of variable geometry difficult, radial ejector configurations have a flow path that is conducive to changes in nozzle and ejector throat area during operation. The geometric adjustment of the radial ejector could be made by simply changing the separation of the radial ejector duct walls and/or the separation of the nozzle walls in order to optimize performance over a range of different conditions. The effects of such changes on the performance of a radial ejector have been investigated using a Computational Fluid Dynamic (CFD) analysis with ANSYS FLUENT software. Axisymmetric CFD models were generated to assess performance for a primary nozzle throat area of 8.792 mm2 and for ejector throat separations of 2.2 mm, 2.4 mm and 3.0 mm, corresponding to ejector throat areas of 497, 543 and 678 mm2, respectively. The CFD analysis reveals that changes ejector performance can be achieved by changing the ejector duct’s separation. An increase of 34% in entrainment ratio can be achieved by increasing the ejector throat separation from 2.2 mm to 3.0 mm at fixed primary and secondary pressures of 160 kPa and 1.8 kPa, respectively. If an increase in the ejector malfunction pressure is needed, it could be achieved by decreasing the ejector duct separation. An overall malfunction pressure increase of 18% can be achieved by decreasing the ejector throat separation from 3.0 mm to 2.2 mm at primary and secondary pressures of 250 and 1.8 kPa, respectively.
Keywords
Radial ejector, air ejector, variable geometry, supersonic radial nozzle
Time
2:35 - 2:55
Authors
Tarek J. Jamaleddine, Ramsey Bunama
Abstract
Compressors are widely used in the petrochemical industry to provide a variety of gas properties that are essential for a variety of chemical processes. Among others, ambient air is predominantly used due to its abundancy in nature and its richness in oxygen. It is customary that clean air is supplied to the compressor by means of a commercial air intake filter placed few meters upstream of the compressor inlet. Various ducting configurations are commercially utilized to link the air filter to the compressor inlet. Embedded baffle-type muzzling units are placed inside the ducting for attenuating acoustic noise generated by the incoming high speed compressible flow. It is imperative that these silencer baffles are aerodynamically structured to maintain constant flow conditions dowsntream of the trailing edge for sustaining an efficient compressor operation. In the Gulf region where ambient temperature condition during hot summer day surpasses 45 oC coupled with saturated moist air, controling and maintaining constant conditions upstream of the compressor inlet pose a great challenge. In this paper, we introduce a numerical study employing Computational Fluid Dynamics (CFD) method for predicting the hydrodynamic conditions within the geometrical entity linking the air filter to the compressor inlet boundary in the presence of a set of symmetrical and cusped trailing-edge aerofoil-shaped silencers. Several baffle locations were investigated to analyze the impact of different locations on the pressure losses and temperature conditions upstream of the compressor inlet. Results show that an optimized silencer location can stabilize the flow conditions upstream of the compressor inlet. Among the considered locations, a recommendation was given for the best location that led to a reduced pressure drop across the bluff body and stabilized inlet conditions to the compressor.
Keywords
CFD, compressors, aerodynamic flows, acoustic baffles, silencers, pressure loss
Time
2:55 - 3:15
Authors
Masoud Darbandi, Ali Fatin, Gerry E. Schneider
Abstract
The impact of flow swirl on heavy fuel oil (HFO) droplet breakup and dispersion is investigated using the finite-volume method. The numerical framework considers suitable models to predict the droplets’ breakups and their dispersions affected by their interaction with turbulence. The validation of chosen models is carried out by comparing the current results with those of previous numerical studies. After validation procedure, three different flow conditions are constructed to expand the study to various swirl number influences. The aim is to investigate the interaction of HFO spraying with the crossed axial swirling flow. The results show that the droplet Sauter mean diameter decreases continuously and the spray becomes finer as the swirling flow strength increases. Dispersion of the finer spray grows up and the spray becomes wider for the stronger swirling flow conditions. Also, the focus on the droplets’ concentration shows that the droplets’ concentration decreases for higher swirl number flows. This reduction is mainly due to the droplets’ dispersion into a larger volume of space. In other words, the spray’s width becomes much wider by increasing the swirling influences. It can be concluded that the strong swirling flow can improve the combustion quality of HFO via improving the mixing process and also via controlling the flame structure. The quantifications are performed subsequently.
Keywords
Heavy Fuel Oil, Swirling Flow, Droplet Breakup, Sauter Mean Diameter (SMD), Dispersion
.

Session

1:05 PM - 3:10 PM | Room: ENG-LG-013

Fluid Flow, Heat and Mass Transfer Equipment
Session Chairs:
Dr. Weiqun Liu, China University of Mining and Technology, China
Dr. Vijay Shankar, Luleå University of Technology, Sweden


Time
1:05 - 1:15
Authors
Merouane Khammar, Yuming Xu
Time
1:15 - 1:25
Authors
Merouane Khammar, Yuming Xu
Time
1:25 - 1:35
Authors
Hoda Azimi, Arian Ebneyamini, Jules Thibault, F. Handan Tezel
Time
1:35 - 1:45
Authors
Fatemeh Bayati, Yaman Boluk, Phillip Choi
Time
1:45 - 2:05
Authors
Ahmed A. Ayash, Jordan M. MacInnes
Abstract
Numerical solution of the governing equations for mass, momentum and species can be used to predict mass transfer in a rotating spiral device. The case of a dilute solute transferring in counter-current gas-liquid flow is considered. Computations in a two-dimensional section of the flow with an existing model for interface shape are used to determine the velocity and solute species fields in each phase. The prediction is assessed along with that of an existing analytical solution for infinite channel width by comparison with some recent mass transfer coefficient data for acetone desorbing from water into air over a range of water flow rates. The computation reproduces the measured results well over the full range of the data. At higher liquid flow rates it is found that secondary motion in each phase generated by Coriolis acceleration acting on the gas phase, causes a doubling of mass transfer coefficient.
Keywords
Rotating spiral channel; mass transfer coefficient; Coriolis secondary motions; interface shape
Time
2:05 - 2:20
Authors
Thariq Mohammed, Wael H. Ahmed, Ashutosh Singh
Abstract
In this study, preliminary experiments were performed in order to evaluate the performance of bioreactor using airlift pump. A patented airlift technology is integrated in a bioreactor and compared to a stirred tank bioreactor. Oxygen mass transfer and water salinity were used to characterize the mixing effectiveness. For the same aeration rate, power consumption is used to compare both conventional and airlift systems at different operating conditions. Also, airlift pump found to create a larger number of bubbles and consequently larger total surface area that allow for more interfacial oxygen transport. The results show a great potential of airlift use in bioreactors to achieve better bioreactor performance with a huge power reduction.
Keywords
Airlift Pump; Mass Transfer; Two-phase Flow, Bioreactor
Time
2:20 - 2:30
Authors
Behnam Mostajeran Goortani, Sayyed Taher Kermani Alghorayshi
Abstract
A gPROMS model for concentrated solar absorption chillers is developed. The advantages of a thermal heat storage system in terms of absorbing drastic solar energy change and storing the energy for working overnight and working during cloudy hours are assumed and calculated in a quantitative manner. The project is an ongoing project supported by Iran Office of Vice-presidency for Science and Technology and has broader objective of practical use of large scale linear Fresnel collectors for cooling applications. Consequently, some preliminary studies were performed. A novel dual axis Fresnel collector with overall dimensions of 12.70 cm by 2.30 cm and total mirrors area of 16.5 m2 is designed and fabricated. A model of receiver, a vacuum tube metal-glass of 20 cm diameter, is first designed and fabricated and tested. CFD modeling with Fluent was utilized to predict velocity and temperature profiles in non-continuous operation mode of the receiver. The profiles of velocity and temperature at receiver angles of 10, 20, 40 and 50 degrees corresponding to the sun elevation angle variations during the year are determined. At the receiver angle of 10 degrees (corresponding to mid-summer), a maximum velocity of 4 cm/s was obtained at the center. The location of this maximum velocity changes toward the wall by increasing the receiver angle.
Keywords
Concentrated solar heat, Absorption chiller, Linear Fresnel collector, CFD modeling
Time
2:30 - 2:40
Authors
Ramtin Barzegarian, Mostafa Keshavarz Moraveji, Alireza Aloueyan, Tooraj Yousefi
Time
2:40 - 2:50
Authors
Behnam Mostajeran Goortani, Elham Khoshandam
Abstract
Spargers are porous devices used for the continuous injection of gas bubbles into liquids. They have many applications like effective aeration in bio reactors, enhanced oil recovery, flotation, filtration and water treatment. In this study low cost spargers are fabricated, utilizing a new method. The bubble sizes and distributions are determined in an experimental setup comprising a bubble column equipped with a semi-professional camera to record the sizes of the bubbles in the column and resulting bubbles are photographed at different gas flow rates. First substrate of glass-bead spargers are fabricated. They are then covered by a layer of copper. The effect of reaction temperature and fluid properties are investigated on the size and the distribution of the produced bubbles. The results showed that the pore size of flat composite sample is decreased to 100 nm by coating by plasma focus deposition device; consequently, all bubbles produced by this sample are less than 0.1 mm inside kerosene. Comparison of BSD for all samples indicated that the smallest bubbles are produced in kerosene. By controlling the sintering conditions and through our innovative reaction and sintering method, we fabricated flat and conical composite spargers that produce 100% bubbles of less than 0.1mm diameter, and in kerosene a foamy bubble column is formed.
Keywords
Sparger, Bubble size distribution, Gas flow rate, Sintering, non-polar liquid
Time
2:50 - 3:10
Authors
T. Cardoso de Souza, S.J.F. Erich
Abstract
In this paper we investigate the convective mass transfer process between a laminar air flow passing over a humid fractal surface. To determine the mass transfer convection coefficient, hm, in complex ‘wetted’ fractal geometries, a simple numerical method is considered to obtain the rate of evaporation for any type of surface. This approach is validated considering two benchmark cases commonly discussed in laminar boundary layer theory, e.g., the flow over a flat plate and the flow over a cylinder. By considering different types of fractal geometries and different air flow speeds, we characterize the effects that such multi-scale fractals have on the convective mass transport driving the surface averaged rate of evaporation, nA. The results show the potential of fractals surfaces to enhance evaporation, where depending on the fractal shape considered, for instance, an increase by more than a factor of 3 in the rate of evaporation was obtained in comparison with a reference case where no fractals structures are imposed.
Keywords
Multi-scale fractal forcing, evaporation enhancement, laminar flows

Session

3:35 PM - 5:55 PM | Room: ENG-LG-006

CFD III
Session Chairs: Dr. Tong Wang, Shanghai Jiao Tong University, China
& Dr. Alexander Liberson, Rochester Institute of Technology, USA


Time
3:35 - 3:55
Authors
Ting Yu, Yinqing Zu, Hongyi Xu
Abstract
The paper applied the state-of-the-art flow simulation method, i.e. the Direct Numerical Simulation (DNS), and strongly coupled the DNS with the heat-transfer governing equation to solve the thermal-turbulence problem in a turbine-blade cooling channel with rib-tabulator structures. In order to capture the thermal-fluid phenomena and to more accurately simulate the flow and temperature fields in reality, two innovative approaches were applied to the simulations. First, the surface roughness effects of the cooling vane was considered by including the roughness geometry in the DNS and an innovative immersed-boundary method were invented to handle the geometry complexities due to the roughness. Secondly, the time-sequencing fully-developed turbulent inflow conditions were generated through the temporal DNS of turbulence in a channel and these conditions guaranteed the qualities of the spatial DNS simulation of cooling vane with ribs, which were expected to provide a variety of advantages over the conventional Reynolds-averaged Navier-Stokes (RANS) approach. The preliminary results presented the typical wall-turbulence characteristics, such as the near-wall coherent structures for a regular smoothed wall and more interesting flow structures caused by a wall roughness. The coupled heat-transfer simulation captured the temperature and its derivative fields, which exhibited the attractive coherent streaky patterns associated with the turbulence.
Keywords
Direct Numerical Simulation, Heat Transfer, Strongly-coupled Simulation, Rib Tabulator
Time
3:55 - 4:15
Authors
Beena D. Baloni, Sonu P. Kumar, S. A. Channiwala
Abstract
A Bell type nozzle is most commonly used shape for rocket nozzles. This type of nozzle not only offers significant advantages in terms of size and performance over the conical nozzle but also reduces complexity compared to annular nozzles. The nozzle uses the stagnation temperature (To) and stagnation pressure (Po) generated in the combustion chamber to create thrust by accelerating the combustion gases to a high supersonic velocity. The nozzle expansion ratio was governed by the exit velocity. During flight, the jet flow is ideally expanded and adapted to the surrounding flow only during a short period. The rest of the time, the rocket engine operates in off-design conditions. The present work incorporates 2D axisymmetric flow analysis within the bell type nozzle, at design and off-design conditions, by using computational fluid dynamic software GAMBIT 2.4.6 and FLUENT 6.3.26. A computer code, with the use of the method of characteristics and stream function, is developed to define the higher efficiency nozzle contours for analysis. Simulation has been carried out separately for two different flow conditions i.e. cold and hot. Shear Stress Transport k-ω turbulence model has been chosen for flow analysis. The converged solutions captured asymmetric lambda shock in the nozzles at higher nozzle pressure ratios (NPR) for viscous flows. It also predicted aftershock and flow separation depending upon NPR. The strength of the normal shock, at Mach stem in viscous prediction, generally increases with an increase in NPR. Good agreement is observed between predicted simulation and analytical results in terms of shock structure, shock location, the size of normal shock, aftershock, and asymmetric lambda shocks.
Keywords
Bell type Nozzle, Numerical Analysis, Compressive Waves (Shock Wave)
Time
4:15 - 4:35
Authors
Beena D. Baloni, Kadiyam Vijay Kumar, S. A. Channiwala
Abstract
In the modern age of aviation, turbofan engines are designed with pressure ratio as high as 40 and by-pass ratios in excess of 8. Multi spool compressor connected with a transition duct fulfils the requirement of high pressure ratio. The inter-stage annular S-shaped transition duct connects the exit of LP compressor to the inlet of HP compressor. Due to the curvature of the duct, turbulence losses and flow separation losses will develop inside the duct. Sometimes, struts are placed inside the duct for better guidance of flow. The present paper incorporates numerical analysis of the compressor transition duct with CFD software ANSYS 15. The S-Shaped compressor transition duct is designed for the 3 stage LP compressor, which operates at mass flow rate 77.8 kg/sec and pressure ratio 3.3. Numerical work consists of flow analysis of the 2D duct, the 3D duct, and the 3D duct with provision of struts. Modeling and flow analysis of the S-shaped duct is carried out with ANSYS 15.0. The results suggest that the total pressure loss is increased from 2D to 3D and 3D without strut to cases of 3D duct with struts.
Keywords
Multi spool compressor, Transition S-shaped duct, Numerical flow analysis
Time
4:35 - 4:55
Authors
Beena D. Baloni, Ashutosh Singh, S. A. Channiwala
Abstract
The paper describes numerical analysis of the centrifugal compressor used in an auxiliary power unit by using CFD software ANSYS 15.0. The fluid domain of centrifugal compressor comprises of impeller, channel diffuser and volute casing. The impeller is designed based on 1-D calculations and impeller geometry is developed based on a code for the blade generation using Kaplan method. Present techniques of correlations are used to develop the diffuser and volute. Whereas; geometry of diffuser and volute are developed using SOLIDWORKS 2013. The components of the compressor stage are individually meshed in the MESH component of ANSYS 15.0 workbench. The turbo mode of CFX 15 is used to develop the setup for analysis. The shear stress turbulence model is used as turbulence model. The frozen rotor interface is applied to take care of stator- rotor interactions. Inlet mass flow and pressure outlet at outlet are kept as boundary conditions. A High resolution advection scheme with first order numeric are chosen and convergence criteria is kept at 10-4. Grid independence study and satisfactory comparison of simulation results with theoretical design calculations are also carried out. The validated simulation case is opted to study the effect of the volute tongue angle and change in shape of the diffuser blade on compressor performance. At the end, all the cases are compared with each other on the basis of uniformity in variation of properties and performance parameters like efficiency and pressure recovery.
Keywords
Centrifugal compressor, Channel diffuser, Numerical flow analysis, Auxiliary power unit
Time
4:55 - 5:15
Authors
Vijay Shankar, Andreas Bengtson, Victor Fransson, Carl-Eric Hagentoft
Abstract
Investigating the heat transfer in porous media is of interest, since a deeper understanding of this phenomenon can be used to improve the energy efficiency of buildings. Heat can be transferred in three ways: conduction, convection and radiation. All these three mechanisms are always present and needs to be taken into account. The forces generated by density gradients in the earth's gravitational field, leads to the so-called natural convective heat transfer, both in fluid and porous media. The presence of temperature gradients, when reaching a certain temperature difference, gives rise to fluid and thermal motion due to the natural convective process. The ability to simulate and compute the combined effects of heat transfer due to conduction, natural convection and radiation are therefore of paramount interest, in order to design the future environmentally friendly, energy efficient and healthy buildings. In this study, the heat transfer through a porous region, representing a layer of insulation, with an air cavity above has been numerically investigated with the help of CFD. The numerical results obtained are validated with experimental results.
Keywords
CFD, Heat Transfer, Porous Media, ANSYS
Time
5:15 - 5:35
Authors
Vijay Shankar, Anton Lundberg, Kristian Frenander, Lars Landström, Taraka Pamidi, Örjan Johansson
Abstract
In order to lower the energy consumption of the fibrillation stage for the pulp and paper industry, a new technology need to be innovated and developed. The current research work deals with a new innovative concept based on creating cavitation in the pulp flow. A venturi nozzle is designed and optimized, where hydrodynamic cavitation is achieved by the so called Venturi effect. This paper focuses on the development of an automatic method for venturi shape optimization. The process of cavitation is hard to control and can cause high mechanical wear, therefore an optimization study of the venturi shape is performed with two main objectives. Firstly, to achieve cavitation that is sustained for as long as possible downstream and secondly to avoid cavitation at the walls. The developed method is a type of two-level optimization based on neural networks and evolutionary optimization. A number of simulations are executed and the optimization is then performed on a solver approximation instead of the real solver, which considerably reduces computation time. The obtained results show the optimal venturi configuration and the relative importance of each shape parameter. The optimal configuration is a clear improvement of the baseline configuration and an improvement also compared to all of the tested samples, thereby validating the optimization method.
Keywords
Cavitation, Neural networks, Optimization, Pulp & Paper, Venturi nozzle
Time
5:35 - 5:55
Authors
Vijay Shankar, Andreas Bengtson, Victor Fransson, Carl-Eric Hagentoft
Abstract
Due to improper design of cold ventilated attics with regard to family homes, mild growth has become an increasing problem in Scandinavia and other cold countries around the globe. In this research paper, the influence of combined natural and forced convection on the thermal properties of insulation is investigated. The governing equations for fluid motion, energy (heat) and suitable turbulence model have been solved with help virtual numerical technique namely CFD. The numerical computations are conducted for two different insulations with varying values of permeability. The results of this complicated and sensitive heat transfer process are presented as function of different inlet velocities, physical properties of insulation and temperature difference across the calculation domain for full scale cold ventilated attics.
Keywords
Computational fluid dynamics (CFD), Heat transfer, Building physics, Fluid mechanics
.

Session

3:35 PM - 4:55 PM | Room: ENG-LG-013

Transport Phenomena in Porous Media
Session Chair: Dr. Behnam Mostajeran Goortani, University of Isfahan, Iran


Time
3:35 - 3:55
Authors
Rupak Banerjee, Chuzhang Han, Nan Ge, Aimy Bazylak
Abstract
Water management is a critical factor in obtaining the highest performance and efficiency from polymer electrolyte membrane (PEM) fuel cells. The liquid water distribution in the individual layers of the PEM fuel cell has a strong impact on performance. The ionic conductivity of the membrane has a strong dependence on membrane hydration. The reactant gases in a PEM fuel cell are supplied through a humidification system to maintain appropriate levels of hydration in the membrane. However, the removal of the anode humidifier would significantly reduce the balance of plant costs and reduce the volume required for the fuel cell in an automotive setting. In this paper, the impact of lower anode humidification on the cell performance and the water distribution in the membrane and the cathode gas diffusion layer were studied. Synchrotron X-ray radiography was used to measure the changes in liquid water quantity in the individual layers. The impact of changing anode humidification on the water distribution is studied. The changes in membrane hydration levels have been measured by the radiographic technique and compared with the changes in membrane resistance.
Keywords
PEM fuel cell; membrane dehydration; synchrotron X-ray radiography; transient changes; anode humidification
Time
3:55 - 4:15
Authors
Arian Ebneyamini, Hoda Azimi, Jules Thibault*, F. Handan Tezel
Abstract
In this study, a model for the prediction of the mass transport through mixed matrix membranes (MMMs) for pervaporation and gas separation processes has been introduced. A Resistance-Based (RB) model was used in conjunction with a Finite Difference (FD) model to derive an analytical model for calculating the effective permeability of mixed matrix membranes. The proposed model was validated using experimental data for the pervaporation and gas separation applications using MMMs.
Keywords
Mixed Matrix Membranes, Effective permeability, Resistance-Based Model, Finite Difference Method
Time
4:15 - 4:25
Authors
Behnam Dastvareh, Jalel Azaiez
Time
4:25 - 4:35
Authors
Mohammad Zargartalebi, Jalel Azaiez
Time
4:35 - 4:55
Authors
W. Q. Liu, Y. S. Li, F. L. Li
Abstract
To better understand the relationship between permeability of fractured rocks and environmental confining pressure, we integrated results from experimental, analytical and numerical methods. In the experiments, we monitor the change in the permeability of fractured sandstone as confining pressure cyclically changes. The analytical models are the combination of hydro-mechanical coupling and fracture equivalence. Numerical simulation is based on the analytical models and used to further interpret the experimental measurements. We find that, 1) fracture permeability changes all by more than 50% for changes in confining pressure from 6MPa to 14MPa, 2) decreasing of fracture permeability with confining pressure has the feature of a negative exponential function, 3) pore pressure does not play an important role on seeping in fractures under high confining pressures, 4) the permeability is always lower in the second load cycle than in the first one for the same confining pressure.
Keywords
Fractured sandstone, Permeability, Cyclic confining pressure, Testing, Simulation

Wednesday
August 23


Room: ENG-LG-006
9:00 AM - 9:45 AM
Keynote Lecture
Pore Network Modelling and in Situ Imaging to Investigate Transport in Polymer Electrolyte Membrane Fuel Cells and Electrolyzers
Dr. Aimy Bazylak, University of Toronto, Canada
9:45 AM - 10:30 AM
Keynote Lecture
Water Extraction from Air: Potential and Limitation
Dr. Jules Thibault, University of Ottawa, Canada
10:30 AM - 11:10 AM
Coffee Break
10:30 AM - 11:10 AM
Session
Poster Session
11:10 AM - 12:50 PM
Session
Fluid Flow
12:50 PM - 2:00 PM
Lunch
2:00 PM - 3:20 PM
Session
Heat transfer
3:20 PM - 3:40 PM
Coffee Break
3:40 PM - 4:30 PM
Session
Two and multiphase flow and heat transfer

Keynote Lecture

9:00 AM - 9:45 AM | Room: ENG-LG-006 | Session Chair: Dr. Boguslaw Kruczek, University of Ottawa, Canada

Pore Network Modelling and in Situ Imaging to Investigate Transport in Polymer Electrolyte Membrane Fuel Cells and Electrolyzers
Dr. Aimy Bazylak, University of Toronto, Canada


Abstract
Polymer electrolyte membrane (PEM) fuel cells and electrolyzers provide the opportunity to enable a renewable energy infrastructure by producing on-demand electricity from renewably sourced hydrogen. However, due to cost and inefficiency barriers, polymer electrolyte membrane (PEM) fuel cells and electrolyzers have not yet reached widespread commercial adoption in the transportation sector. Mass transport limitations arising from liquid water flooding in low temperature PEM fuel cells leads to inefficiencies. If these issues become resolved, smaller and more reliable devices could be produced at a lower cost. Mass transport limitations can be minimized through the development of optimized materials, which have tailored pore structures, connectivities, conductivities, and surface wettabilities. The porous materials in PEM fuel cells and electrolyzers could be customized for mass transport with detailed information about their structure and the dominating mass transport mechanisms that result from these structures. In this talk, visualization techniques, such as microcomputed tomography, synchrotron X-ray radiography, and neutron radiography for investigating multiphase transport in PEM fuel cells and electrolyzers, will be discussed. The combination of these experimental diagnostic tools with pore network modelling will be discussed as a unique platform for investigating the transport behaviour of liquids and gases in electrochemical conversion technologies.

Keynote Lecture

9:45 AM - 10:30 AM | Room: ENG-LG-006 | Session Chair: Dr. Boguslaw Kruczek, University of Ottawa, Canada

Water Extraction from Air: Potential and Limitation
Dr. Jules Thibault, University of Ottawa, Canada


Authors
S. Gh. Etemad, M. Haghshenas Fard, B. Kruczek, E. Jara-Morante, J. Thibault
Abstract
Collecting water from atmospheric air by condensation can help to partly alleviate water shortage in different regions of the world. Liquid water can be obtained when a surface exposed to moist air reaches a temperature that is below the dew point temperature. The surface can be cooled using a coolant or naturally by radiating to a clear night sky. This investigation examines the latter. The efficiency of this condensation process depends on numerous parameters such as the emissivity of the condensing surface, wind speed, air relative humidity, and air temperature. Through numerical simulations, the role of these parameters on the collector plate temperature and condensation rate was examined. Results show an interesting role of the wind speed on the resulting condensation rate on the plate. On the one hand, as the wind speed increases, the plate temperature increases, thereby resulting in a decrease in the driving force for condensation. On the other hand, the mass transfer coefficient for the transport of the water vapour from bulk air to the plate increases with the wind speed. The latter effect is stronger than the former one, therefore for the wind speeds for which the plate remains below the dew point temperature, the condensation rate increases with the wind speed. The effects of the relative humidity and the ambient air temperature were also examined to determine how they impact the ability of passive collectors to condense water.

Session

10:30 AM - 11:10 PM | The Poster Session will be taking place in the hall next to room ENG-LG-015

Poster Session
Session Chairs:
Dr. Alexander S. Liberson, Rochester Institute of Technology, USA
Dr. Gilbert Makanda, Central University of Technology, South Africa


Authors
Ying Liu, Suli Liu, Zhiwen Che, Wei Wang, Jianchun Bao, Zhihui Dai
Authors
Ru Yang, Hui-Ling Zeng
Authors
Ryan Poon, Igor Zhitomirsky
Authors
Muath Alomair, Yazeed Alomair, Hussein Abdullah, Syeda Tasnim
Abstract
Thermal energy storage (TES) using phase change materials (PCMs) are an efficient and reliable technique to reduce consumption of energy. The heat transfer processes during phase change in PCMs is complex because of the simultaneous presence of solid and liquid phases where, solid and liquid fractions are continuously changing with time. The present experimental investigation focuses on the transient behaviour of the melting process and the dynamic of the solid-liquid interface in a cylindrical TES containing bio-based PCM. Coconut oil is used as a bio-based PCM and two different experimental conditions are investigated. The aim of this study is to improve the understanding of the fundamental of solid-liquid phase transition during melting, and a better characterization of the related heat transfer during phase change processes of bio-based PCM. To achieve these goals, an experimental setup is developed for the visualization of charging time, melt fraction location, and thermal field measurements.
Keywords
Phase change materials, Melting, Bio-based PCM, Experimental investigation
Authors
M. Alomair, Y. Alomair, H.A. Abdullah, S. Mahmud, S.H. Tasnim
Abstract
Latent heat thermal energy storage (LHTES) system uses a phase change material (PCM) to store or release thermal energy, thus reducing the overall consumption of energy in a system. But, the problem with the PCM is their low thermal conductivity that increases the melting and solidification time, which is not suitable for specific application areas, such as, battery thermal management, electronic cooling etc. To increase the thermal conductivity of PCM, different studies examine different approaches including extension of the heat transfer area using fins and honeycombs, thin metal strips, porous metals, copper chips, metal foam matrices, metal screens and spheres, carbon fiber brushes and chips, graphite matrices, microencapsulated PCM, multiple PCMs, carbon-based nanostructures graphene flakes, carbon nano-tubes, metallic nanoparticles, silver nano-wires, and bio-based composite PCM. The current study incorporates nanoparticle in PCM (nano-PCM) to increase the thermal conductivity of the PCM. Experimental studies are performed using Copper Oxide (50nm) and Aluminum Oxide (50nm) nanoparticles supplied by Sigma Aldrich and Rubitherm (RT-18) as base PCM, supplied by Rubitherm GmbH. The vertical cylindrical LHTES is composed of two concentric pipes; with the inner one carrying a heat transfer fluid at a constant temperature and the annular space containing a nano-PCM. The initial temperature of the nano- PCM is 5 C while the temperature of the heat transfer fluid is 40 C. The experimental results show that using nano-PCM reduces the melting time when compared to base PCM, but enhanced melting is observed when Copper Oxide nanoparticle is used.
Keywords
Melting; Latent heat thermal energy storage; Phase change material; Nanoparticles: Thermal conductivity
Authors
Cameron Wallar, Igor Zhitomirsky
Authors
Jun Yin, Zhongjie Zhang, Xiaomeng Wang, Qu Yao, Zidan Wu
Abstract
In stored-grain bulk, its state would be affected by the coupling actions of temperature, humidity, moisture, gas and so on. However the most important factors are temperature and humidity. In the paper, the wheat was sealed in the 30 ℃ temperature difference simulation bin for about 75d. The results indicated that the fastest of the temperature change rate was the upper of grain bulk in the same vertical direction of the same plane. In the same way, the grain with nearer to the high temperature district was faster temperature rise and higher amplitude. To the relative humidity of grain bulk, the change of the close to higher temperature grain zone was fiercer than the others. And the relative humidity of low temperature area would change gently. The micro-airflow in grain mainly stemmed from the temperature differences. So the migration and redistribution of the temperature and relative humidity in wheat bulk was caused by the actions of conduction and convection. And the convection was the predominant action in grain bulk. In addition, the differences between heat and mass transfer in vertical and horizontal direction could demonstrate that the grain is anisotropy.
Keywords
Temperature, relative humidity, micro-airflow, anisotropy
Authors
Liyong Wang, Le Li
Authors
M. K. Cho, J. W. Lee
Authors
Kohei Obara, Sinisa Krajnovic, Guglielmo Minelli, Nobuyuki Okura, Masahiro Suzuki
Authors
Kyehan Rhee, Pengsrorn Chhai
Authors
Huan J. Keh, Cheng Y. Li
Authors
Jaeseon Lee, Dongkook Joo
Authors
Laribi Boualem, Abdellah Hadj Abdellah
Abstract
This paper present a numerical experimentation of the behaviour of the discharge coefficient and the effect of four perforated plates like flow conditioners on the discharge coefficient for flow measurement accuracy. Three of the plates are described by the Standard ISO5167 and the fourth one is proposed for study. The flow is subject to two disturbers namely 50% closed valve and 90 double bend in perpendicular planes. The turbulent flow is examined in conduit with an inner diameter of D=100mm. The diameter of orifice meters are respectively d=50, 60, 70 and 75mm which done for  ratio d/D respectively the values of 0.5, 0.6, 0.7 and 0.75. The orifice meters are located in conduit at different stations z/D downstream the disturbers. The flow is examined with air at Reynolds number Re=2.5x105. The results showed that the perforated plates have significantly reduced the error on the discharge coefficient. Indeed, the errors recorded downstream disturbers are superior to 12%. Downstream the perforated plates used separately the errors on the discharge coefficient are reduced to a value inferior to 1% for the four plates. It is noted that the standards ISO5167 and AGA3 stipulate that the error on the discharge coefficient Cd must be less than 0.5% for better flow measurement accuracy. By comparing our results with this condition we found that the error obtained on the discharge coefficient with the four perforated plates are substantially reduced especially downstream station z=25D (z =19D downstream disturbers). However the fourth proposed plate with its height porosity produces less lose pressure than those of the other three plates. This is good conditions of exploitation for some installation where height lose pressure are not tolerated.
Keywords
Perforated plates flow conditioners, flowmetring, discharge coefficient.
Authors
Sae Byul Kang, Hyun Hee Lee, Kyu Sung Choi, Jong Jin Kim, Jae Joon Choi, Byung Joo Lee, Jong Hoon Kim, Chi Kwan Kim
Authors
Moosun Kim, Jung-Seok Kim
.

Session

11:10 AM - 12:50 PM | Room: ENG-LG-006

Fluid Flow
Session Chair: Dr. Aimy Bazylak, University of Toronto, Canada


Time
11:10 - 11:30
Authors
Hesham A. Ibrahim, Sherif Abdou, and Wael H. Ahmed
Abstract
In this experiment the fluid flow behaviour through an automotive catalytic converter has been studied empirically and computationally. A CFD model utilizing the k-ω turbulence model and porous media approach was developed to simulate the flow through the monolithic ceramic substrate. The flow properties for the ceramic monolith were obtained using a 3D single channel approach. CFD analysis was validated by flow experiments with non-reacting flow using high temperature air. The local velocity and temperature profiles for inlet Reynolds Number of 43,000 were measured using hot-wire and high sensitivity thermocouple sensors. The CFD results were found to predict the experimental measurements with an average root mean square error of ±8%. The present analysis is considered to be a key step towards understanding the flow behaviour through catalytic converters that can help in achieving better design of the exhaust system.
Keywords
Flow Distribution; Catalytic Converter; Thermalhydraulic Performance
Time
11:30 - 11:50
Authors
Alexander S. Liberson, Yashar Seyed Vahedein
Abstract
Microscale effects become important, when the mean free path of the energy carrier becomes comparable to the characteristic length of the object. In such scale the continuum approach based on a heuristic principle of continuity is no longer valid. Modeling microflows requires to take into account the Knudsen number – the dimensionless characteristics of microscale. This is because the concept of continuity in microscale fails being applied to the finite volumes, characterized by a mean free path, or the size of a microstructural lattice. In order to account for the microstructure the higher order continuum approximation is proposed which is based on a continualization strategy inside microstructural volume and a relating variational principle. The basic generalized equations are derived and presented for fluid mechanics with applications to microstructure. Boundary conditions for the generalized mathematical model are derived based on application of a virtual work variational principle. The impact of a slip boundary condition on a velocity distribution and a mass flow rate is analyzed for a wide range of Knudsen number. It was found that the correct application of a slip boundary condition links closely to the applied gradient model. It is shown that the combination of slip boundary conditions with the classical model for the laminar flow results in a noticeable overestimation of the predicted mass flow rate. In contrast to the number of gradient models, requiring a large number of phenomenological constants, the present model requires at least one additional constant, linked to the microscale characteristic length.
Keywords
Microscale, gradient model, viscous flow, slip boundary conditions
Time
11:50 - 12:10
Authors
Heyan Li, Mingyang Li, Biao Ma, Jikai Liu, Liang Yu, Huizhu Li
Abstract
A multi-disc clutch test bench was set up and sliding experiments were conducted to investigate the relationship between the friction glazed spot distribution and mechanical torsion buckling on frictional components. The buckling deformation model of a separator disc with spline teeth subjected to mechanical torsion is established to compare with the experimental observation. The buckled spline disc provides a certain perturbation frequency during the sliding period. Under this sliding condition, when the relative sliding rubbing speed in frictional clutches exceeds the thermoelastic instability (TEI) speed predicted by Barber and Lee’s TEI model, mechanical buckling induces thermoelastic instability (MBTEI). The dangerous sliding speed and perturbation pressure growth rate are obtained in regard to structural parameters, temperatures, abrasion cracks and torques.
Keywords
Clutch; spline separator discs; mechanical torsion buckling; thermolelastic instability
Time
12:10 - 12:30
Authors
Gilbert Makanda
Abstract
Natural convection from a spinning sphere with temperature dependent viscosity, thermal conductivity and viscous dissipation was studied. A unique system of non-similar partial differential equations was solved using the bivariate local-linearization method (BLLM). This method use Chebyshev spectral collocation method applied in both the η and ξ directions. Similar equations in the literature are normally solved by inaccurate time-consuming finite difference methods. This work introduces a robust method for solving partial differential equations arising in heat and mass transfer. The numerical method was validated by comparison to the results previously published in the literature. The method is fully described in this article and can be used as an alternative method in solving boundary value problems. This work also presents rarely reported results of the effect of selected parameters on spin-velocity profiles g(η).
Keywords
Free convection, spinning sphere, local linearization
Time
12:30 - 12:50
Authors
Mehdi Mortazavi, Kazuya Tajiri
Abstract
In this paper, liquid-gas two-phase flow pressure drop in proton exchange membrane (PEM) fuel cell is studied in an ex-situ experimental setup. The two-phase flow pressure drop is measured during liquid water droplet emergence and growth on the surface of the gas diffusion layer (GDL). The two-phase flow pressure measurement is synchronized with a high speed camera that records droplet emergence and growth. Simultaneous study of droplet size and liquid-gas two-phase flow pressure drop reveals useful information which can be utilized in analyzing existing two-phase flow pressure drop models.
Keywords
PEM fuel cell, two-phase flow, pressure drop, droplet
.

Session

2:00 PM - 3:20 PM | Room: ENG-LG-006

Heat Transfer
Session Chair: Dr. Mehdi Mortazavi, Western New England University, USA


Time
2:00 - 2:20
Authors
Mohammadhossein Hajiyan, Shohel Mahmud, Mohammad Biglarbegian, Hussein A. Abdullah
Abstract
In this paper, the natural convection heat transfer process is investigated inside an annular enclosure filled with a magnetic nanofluid (Fe3O4 magnetic nanoparticles dispersed in Kerosene). A uniform magnetic field (H) is applied along the axial direction of the enclosure. Thermal conductivity (k) is considered as a function of magnetic field. A nonlinear relationship between magnetic field and thermal conductivity in the magnetic nanofluid (MNF) is assumed and interpolated. Finite element method is utilized to solve the governing equations and calculate the Nusselt number and it is presented as a function of volume fraction and magnetic field strength. The results show the significant effect of applied magnetic field on heat transfer rate, more specifically on Nu, in the enclosure when higher volume fractions of nanoparticles are used. Thermal conductivity enhancement as a result of using magnetic field can be used for various applications such as thermal energy storage in which the heat transfer needs to be accurately controlled.
Keywords
Magnetic nanofluid (MNF), Thermal conductivity, Lorentz force, Natural convection
Time
2:20 - 2:30
Authors
Hiroki Takiguchi, Masahiro Furuya, Takahiro Arai
Time
2:30 - 2:50
Authors
Marco Simonetti, Christian Caillol, Pascal Higelin, Clément Dumand, Emmanuel Revol
Abstract
There are many engineering practical situations where heat is transferred under conditions of pulsating flow such as in the exhaust pipes of Internal Combustion Engines. In these conditions, heat transfer mechanism is affected by the pulsating flow parameters. The objective of the present work is to experimentally investigate heat transfers for pulsatile turbulent flows in a pipe. A unique experimental apparatus able to reproduce a pulsating flow representative of the engine exhaust has been designed. A stationary turbulent hot air flow with a Reynolds number of 30000, based on the time average velocity, is excited through a pulsating mechanism and exchanges thermal energy with a steel pipe. Pulsation frequency ranges from 10 to 95 Hz. The effects of pulsation frequency and pipe length are evaluated. It has been observed that flow pulsation enhances convective heat transfers in comparison with the steady case. The test-bench architecture let us to evidence that, when the flow is excited with a pulsation frequency equal to one of the resonance modes of the system, a local maximum of the heat transfers rate appears. Such behaviour has been found to be independent of the pipe length. Results also show that the actual Nusselt correlations to predict convective heat transfer are inaccurate for pulsating flows, suggesting that new correlations which account pulsation effects have to be proposed.
Keywords
Convective Heat Transfer Enhancement, Pulsating Flow, Internal Combustion Engine, Waste Heat Recovery
Time
2:50 - 3:00
Authors
Shu-San Hsiau, Li-Tsung Sheng, Shao-Li Chiu
Time
3:00 - 3:20
Authors
Mohammad Reza Tavakoli, Mahsa Farzaneh, Arash Shadlaghani
Abstract
This paper attempted to numerically examine the involvement of serrated fins on natural convection heat transfer between coaxial cylinders. The outer channel of annular cylinders was circular, while the inner channels involved three cross-sections including circular, square and triangular. As two geometric constraints, the area of annular cylinders and the diameter of outer channel were assumed to be identical in each scenario explored in this study. The fins had equal areas placed on the inner surface, so as to compare their effects on thermal properties of annular cylinders under constant temperature boundary within the range of Rayleigh numbers from 105 to 108. The results indicated that higher a Rayleigh number is directly correlated with higher convection heat transfer coefficient of surfaces. However, the inclusion of fins reduced the rate near the fins, thus mitigating the heat transfer coefficient of inner channel. This trend intensified at higher Rayleigh numbers. Therefore, the involvement of fins at lower Rayleigh numbers brings about greater efficiency in heat transfer. The comparison of fins in terms of efficiency revealed that maximum heat is transferred when the fins have been mounted on a circular channel.
Keywords
Coaxial Annular Cylinders, Natural Convection, Fins, Numerical Simulation
.

Session

3:40 PM - 4:30 PM | Room: ENG-LG-006

Two and Multiphase Flow and Heat Transfer
Session Chair: Dr. Vijay Shankar, Luleå University of Technology, Sweden


Time
3:40 - 4:00
Authors
Shaker S. Bukhari, Wael H. Ahmed
Abstract
The performance of airlift pump is dependent on the complex two-phase flow analysis that has yet not been optimized to its full potential for aquaculture applications. In this study, initial effort on the optimization of airlift pump performance for the highest efficiencies has been carried out. Two different optimization techniques were used in the present study including the minimum of constrained nonlinear multivariable function and the Genetic Algorithm. Both method were evaluated experimentally at different pump operating conditions. The experimental results show reasonable agreement with the Genetic Algorithm over a wide range of submergence ratio and air flow rates. Although, the optimization algorithms found to offer simple analysis when trying to setup an airlift pump for an aquaculture application, however, two-phase flow modelling taking into account the operating flow pattern is considered to be the best in evaluating the airlift pump performance.
Keywords
Airlift pump, Aquaculture, Two-phase flow, Optimization, Genetic algorithm
Time
4:00 - 4:20
Authors
Adam Johns, Eleanor Merson, Raphael Royer, Harvey Thompson, Jonathan Summers
Abstract
Internal coolant channels are a common method of transporting large thermal loads away from the tool in twist-drill machining to increase tool life and to aid chip evacuation and avoid catastrophic tool failure. A finite element model, loosely coupled with a multiphase Computational Fluid Dynamics (CFD) model is used to investigate the distribution of coolant in the bore hole and the effect of channel position on cutting geometry lubrication. The use of response surface models show that all designs do not fully flood the bore hole and that not all areas of the tool geometry are lubricated with coolant. Visual analysis of CFD results show that coolant, for all designs, primarily lubricates the area between the cutting edge and the coolant hole exit, however depending on application requirements coolant channel positioning can be used to modify coolant supply to the axial rake, for chip evacuation or to the cutting edge for heat removal.
Keywords
Drilling Coolant CFD OpenFOAM VOF
Time
4:20 - 4:30
Authors
Abdullah M. Kuraan, Victoria J. Centofanti, Yunus Ulus, Kyosung Choo