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Divyprakash C. Pal, Abhik Majumder^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.1
Abstract In this present work heat transfer characteristics, thermal performance and pressure drop are studied numerically for a finned-tube bank heat exchanger with Delta Winglet Vortex Generator (DWVG) on the fin at different angle of attack (α). The thermo-fluid is studied by varying α at 15o , 25o , 30o and 35o . The base length (lDW) of the winglet also varied from 20mm to 35mm. The heat transfer coefficient and pressure drop increased in all the cases with increase in Reynolds number. However, significant increase in heat transfer of about 23.92% was observed for α at 35o when compared with… More >

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P.V.S. Kamalakar^a,*, R. Raghavender Rao^a, D.R.V. Prasada Rao^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.2
Abstract In this paper we discuss the effect of chemical reaction and thermal radiation on unsteady free convective heat and mass transfer flow through a porous medium in a vertical wavy channel. The unsteadiness in the flow is due to the oscillatory flux in the flow region. The coupled equations governing the flow, heat and mass transfer have been solved by using a perturbation technique with the slope  of the wavy wall as the perturbation parameter. The expression for the velocity, the temperature, the concentration, the rate of heat and mass transfer are derived and are analyzed for different variations… More >

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Junjie Chen^*, Wenya Song, Xuhui Gao, Longfei Yan, Deguang Xu
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.3
Abstract The flame stability of single-pass heat-recirculation micro-combustors was investigated using computational fluid dynamics and compared to singlechannel micro-combustors with respect to critical heat loss coefficient and total power loss. The effect of wall thermal conductivity was also explored. The simulations show that heat recirculation profoundly affects blowout because of preheating of the cold incoming gases but has only minimal effect on extinction. In the limit of low-conductivity walls, the heat-recirculation micro-combustor is much more stable than the single-channel microcombustor. Under certain conditions, the heat recirculation micro-combustor can operate with room-temperature inlet and outlet streams and moderate outer wall temperatures while… More >

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Wubshet Ibrahim^∗
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-10, 2016, DOI:10.5098/hmt.7.4
Abstract The study scrutinizes the effect of convective heating on magnetohydrodynamic (MHD) stagnation point flow and heat transfer of upper-convected Maxell fluid p ast a s tretching s heet i n t he p resence o f n anoparticles. T he m odel u sed i n t he s tudy i ncludes t he e ffect o f B rownian m otion and thermophoresis parameters. The non-linear governing equations and their boundary conditions are initially cast into dimensionless forms by similarity transformation. The resulting system of equations is then solved numerically using fourth order Runge-Kutta method along with shooting technique.… More >

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Viraj S. Shirodkar^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.5
Abstract Urea-water solution droplet evaporation is modelled using multi-component droplet evaporation approach. The heat and mass transfer process of a multi-component droplet is implemented in the Langrangian framework through a custom code in ANSYS-Fluent R15. The evaporation process is defined by a convection-diffusion controlled model which includes the effect of Stefan flow. A rapid mixing model assumption is used for the droplet internal physics. The code is tested on a single multi-component droplet and the predicted evaporation rates at different ambient temperatures are compared with the experimental data in the literature. The approach is used to model the injection of urea-water… More >

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K. Kaladhar^a,∗, D. Srinivasacharya^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-10, 2016, DOI:10.5098/hmt.7.6
Abstract This present investigation carried out the effects of Hall current, Joule heating and the thermal diffusion on mixed convection flow of electrically conducting couple stress fluid in a vertical channel saturated with porous medium. The final system of ordinary differential equations are obtained from the governing non-linear partial differential equations by using the similarity transformations. Homotopy Analysis Method has been used to solve the non-linear system. The average residue errors of the HAM solutions are presented through graphs. The influence of the emerging parameters (Hall, Soret, magnetic and the couple stress parameters) on velocity, temperature and concentration profiles are presented… More >

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Nazia Afrin^a, Yijin Mao^a, Yuwen Zhang^a,*, J. K. Chen^a, Robin Ritter^b, Alan Lampson^b, Jonathan Stohs^c
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.7
Abstract A three-dimensional numerical simulation is conducted for a complex process in a laser-material system, which involves heat and mass transfer in a compressible gaseous phase and chemical reaction during laser irradiation on a urethane paint coated on a stainless steel substrate. A finite volume method (FVM) with a co-located grid mesh that discretizes the entire computational domain is employed to simulate the heating process. The results show that when the top surface of the paint reaches a threshold temperature of 560 K, the polyurethane starts to decompose through chemical reaction. As a result, combustion products CO₂, H₂O and NO₂ are… More >

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P.V. Satya Narayana^a,*, B.Venkateswarlu^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-10, 2016, DOI:10.5098/hmt.7.8
Abstract In this paper, we study the chemical reaction and heat source effects on unsteady MHD free convection heat and mass transfer of a nanofluid flow past a semi-infinite flat plate in a rotating system. The plate is assumed to oscillate in time with steady frequency so that the solutions of the boundary layer are the similar oscillatory type. The innovation of the present work is closed-form analytic solutions are obtained for the momentum, energy and concentration equations. The influence of various parameters entering into the problem in the nanofluid velocity, temperature and concentration distributions, as well as the skin friction… More >

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Mekonnen Shiferaw Ayano^*, J. S. Mathunjwa
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.9
Abstract This paper presents a study of the Magnetohydrodynamic flow of incompressible micropolar fluid past an infinite vertical porous plate with combined heat and mass transfer. The plate oscillate harmonically in its own plane and the temperature raised linearly with respect to time. Numerical calculations are carried out for different values of dimensionless parameters and an analysis of the results shown graphically and in table form. It is found that velocity and microrotation influenced appreciatively with parameters like radiation, magnetic, chemical reaction and coupling numbers. It is also noted that microrotation highly influenced by the magnetic parameters. The effects of some… More >

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A. Vijayalakshmi, S. Srinivas^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-11, 2016, DOI:10.5098/hmt.7.10
Abstract In the present study, the flow and heat transfer characteristics of a nanofluid in an expanding or contracting porous channel with different permeabilities in presence of thermal radiation are investigated. Analytical solutions for the flow variables are obtained by employing homotopy analysis method (HAM). Maxwell-Garnetts and Brinkman models are considered to calculate the thermal conductivity and the viscosity of nanofluid. In this investigation, we considered water and ethylene glycol as base fluids and silver ( Ag ), copper ( Cu ), titanium dioxide ( TiO₂ ) and alumina ( Al₂O₃ ) as nanoparticles. The effects of various emerging parameters on… More >

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G. Nagaraju^a,† , Anjanna Matta^b, K. Kaladhar^c
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-5, 2016, DOI:10.5098/hmt.7.11
Abstract A theoretical steady of two-dimensional and MHD couple stress fluid flow over a linearly stretching sheet is investigated with the effects of thermal radiation, internal heat generation and homogeneous chemical reaction of first order. The governing equations of continuity, momentum, energy and diffusion for this boundary layer flow are transformed into one set of coupled non-linear ordinary differential equations using the local similarity transformation and are then solved using the fourth-order Runge-Kutta method along with the shooting technique. The effects of the couple stress parameter (S), Magnetic parameter (M) and chemical reaction parameter (Cr) are presented through the graphical illustrations.… More >

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D. Lourdu Immaculate^a , R. Muthuraj^b,*, Anant Kant Shukla^c, S. Srinivas^d
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-14, 2016, DOI:10.5098/hmt.7.12
Abstract This article aims to examine the MHD unsteady flow of Williamson nanofluid in a vertical channel filled with a porous material and oscillating wall temperature. The modeling of this problem is transformed to ordinary differential equations by collecting the non-periodic and periodic terms and then series solutions are obtained by using a powerful method known as the homotopy analysis method (HAM). The influence of involved parameters on heat and mass transfer characteristics of the fluid flow is computed and presented graphically. Further, variations on volume flow rate, coefficient of skin friction, heat transfer rate and mass transfer rate are also… More >

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Seyed Ehsan Rafiee^*, M. M. Sadeghiazad
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-15, 2016, DOI:10.5098/hmt.7.13
Abstract The aim of this investigation is study on separation phenomenon inside a special vortex tube affected by structural and physical factors including; throttle diameter, nozzle number and injection pressure as well as the parametric optimization based on separation efficiency using experimental and 3D-CFD methods. The results show that convergent VT with Dth=5.5mm provides 30.01% and 20.04% higher cooling and heating effectiveness compared to basic model. As another result, the higher injection pressure, the higher cooling effectiveness. The cooling effectiveness improves (16.86%) with increase in slot number up to N=4, then decreases. The maximum disagreement between experimental and predicted values is… More >

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C. S. K. Raju^a , N. Sandeep^a, J. Prakash^b,1
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.14
Abstract In this study, we analyzed the effects of nonlinear thermal radiation and induced magnetic field on steady two-dimensional incompressible flow of Jeffrey fluid flow past a stretching/shrinking surface in the presence of homogeneous-heterogeneous reactions. For physical relevance in this study we analyzed the behavior of homogeneous and heterogeneous profiles individually. The transformed governing equations with the help of similarity variables are solved numerically via Runge-Kutta and Newton’s method. We obtained better accuracy of the present results by differentiating with the existed published literature. The effect of pertinent parameters on velocity, induced magnetic field, temperature and concentration profiles along with the… More >

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Sharath Kumar, Harsha Kumar, N. Gnanasekaran^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.15
Abstract The paper reports the estimation of volumetric heat generation (qv) from a Teflon cylinder. An aluminum heater, which acts as a heat source, is placed at the center of the Teflon cylinder. The problem under consideration is modeled as a three dimensional steady state conjugate heat transfer from the Teflon cylinder. The model is created and simulations are performed using ANSYS FLUENT to obtain temperature data for the known heat generation qv. The numerical model developed using ANSYS acts as a forward model. The inverse model used in this work is Artificial Neural Network (ANN). Estimation of heat generation is… More >

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B. Venkateswarlu^a, P.V. Satya Narayana^b,*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.16
Abstract This paper studies the Soret and Dufour effects on MHD flow of a Casson fluid past a stretching sheet in the presence of chemical reaction, viscous dissipation and variable thermal conductivity. The fluid is taken to be electrically conducting and the flow is induced by a stretching surface. The governing partial differential equations are transformed into non-linear ordinary differential equations using similarity transformations. The resulting equations are then solved numerically by shooting method. The impact of various stimulating parameters on the flow, heat and mass transfer characteristics are analyzed and discussed in detail through graphs. It is observed that the… More >

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Seyed Milad Mirabedin^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.17
Abstract This work focuses on numerical validation of natural convection heat transfer of TiO2-water nanofluids in a cylindrical container using COMSOL. The main aim of this study is to examine different available approaches to calculate effective thermal conductivity and compare them with experimental data available in the literature. Simulation results show that for considered mixture, average Nusselt number decreases by increasing Rayleigh number and particle volume fraction. It has been found that only one model was able to represent similar trends for given particle volume fractions, compared to experimental results. More >

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Kun Zhang^*, Liang Bi Wang
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.18
Abstract Detailed numerical analysis is presented for the effect of spaceship orbital transfer on solution convection during protein crystal growth under microgravity. The results show that the flow and mass transfer during protein crystal growth are unsteady in the process of orbital transfer. For the case of quasi-steady acceleration, the flow is so weak that the effect of flow on concentration field can be negligible. For the case of position adjustment, the convection is enhanced with protein crystal diameter d_c > 0.2 mm and slightly alters the purely diffusive concentration distribution under zero gravity condition. For the case of motor working,… More >

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Vandana Bisht^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.19
Abstract In this paper the steady laminar magneto hydrodynamic (MHD) mixed convection boundary layer flow towards a vertical stretching sheet with variable fluid viscosity, radiation and in the presence of Dufour’s effect have been investigated. The governing partial differential equations are transformed into set of ordinary differential equations using similarity transformation, and then these equations have been solved numerically using Runge- Kutta method with shooting technique. Results shows that magnitude of skin friction coefficient decreases, while magnitude of heat transfer coefficient and mass transfer coefficient increases with decreasing values of viscosity variation parameter for the case of opposing flow. But in… More >

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L. Ramamohan Reddy^a , M. C. Raju^b,*, G.S.S. Raju^c, N. A. Reddy^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-12, 2016, DOI:10.5098/hmt.7.20
Abstract This investigation presents an analytical study on magnetohydrodynamic (MHD), convective flow of a viscoelastic, incompressible, radiative, chemically reactive, electrically conducting and rotating fluid through a porous medium filled in a vertical channel in the presence of thermal diffusion. A magnetic field of uniform strength is applied along the axis of rotation. The fluid is assumed to act on with a periodic time variation of the pressure gradient in upward direction vertically. One of the plates is maintained at non-uniform temperature and the temperature difference of the walls of the channel is assumed high enough that induces heat transfer due to… More >

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S. Harinath Reddy^a , M.C. Raju^a,*, E. Keshava Reddy^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.21
Abstract This manuscript presents a detailed numerical study on the influence of radiation absorption and chemical reaction on unsteady magneto hydrodynamic free convective heat and mass transfer flow. A heat generating Casson fluid past an oscillating vertical plate embedded in a porous medium in the presence of constant wall temperature and concentration is considered. The non-dimensional governing equations along with the corresponding boundary conditions are solved using Finite difference method numerically. Effects of various emerging flow parameters on concentration, temperature and velocity distributions are presented graphically and analyzed. Expressions for skin-friction, Nusselt number and Sherwood number are also obtained. Effects of… More >

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Amnart Boonloi^a, Withada Jedsadaratanachai^b,*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-16, 2016, DOI:10.5098/hmt.7.22
Abstract The numerical investigations on flow structure, heat transfer characteristic and thermal performance in a circular tube heat exchanger with various shapes of winglet vortex generators are reported. The rectangular winglet vortex generators (RWVG), delta winglet vortex generators (DWVG) and curve winglet vortex generators (CWVG) are inserted in the middle of the test tube on both downstream and upstream arrangements. The effects of blockage ratios; BR = 0.1 – 0.3, with single pitch ratio (PR = 1) and flow attack angle (α = 30o) on thermal performance are studied for the Reynolds numbers; Re = 100 – 2000. The numerical results… More >

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G. S. Seth^a,*, P. K. Mandal^a, A. J. Chamkha^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-12, 2016, DOI:10.5098/hmt.7.23
Abstract A theoretical investigation of unsteady hydromagnetic free convection flow with heat and mass transfer of a viscous, incompressible, electrically conducting, optically thick radiating and chemically reactive fluid near an impulsively moving vertical plate with ramped heat flux through fluid saturated porous medium in the presence of inclined magnetic field is carried out. Exact solutions of the governing equations for fluid velocity, fluid temperature and species concentration are obtained by Laplace transform technique. The expressions for the skin-friction, rate of mass transfer at the plate and plate temperature are also derived. Numerical results for fluid velocity, fluid temperature and species concentration… More >

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J. K. Singh^a,*, N. Joshi^a , S. G. Begum^a, C. T. Srinivasa^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-12, 2016, DOI:10.5098/hmt.7.24
Abstract In the present analytical study, we have considered unsteady hydromagnetic heat and mass transfer natural convection flow of an electrically conducting, heat absorbing and chemically reacting fluid past an exponentially accelerated vertical plate in a uniform porous medium taking Hall current and rotation into account. The species concentration near the plate is considered to be varies linearly with time. Two particular cases for plate temperature are considered i.e. (i) plate temperature is uniform and (ii) plate temperature varies linearly with time and after some time it is maintained at uniform temperature. The coupled partial differential equations governing the fluid flow… More >

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Ankit Kanor, R Manimaran^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-5, 2016, DOI:10.5098/hmt.7.25
Abstract One of the effective liquid cooling techniques for microelectronic devices is attaching micro channel heat sink to the inactive side of chip. A micro channel heat sink is a device that decreases temperature by flowing coolant through micro channels. The present study focuses on the conjugate heat transfer analyses for different cross-sections (trapezoidal, hexagonal, octagonal and circular).After present study is validated with the published result in the literature, the comparative study of parallel and counter flow configuration is performed. Different geometries are modeled using CATIA V5 software and simulated in ANSYS Fluent R14. From these CFD simulations, preferred configuration of… More >

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Lioua Kolsi^a,b,*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-10, 2016, DOI:10.5098/hmt.7.26
Abstract In this study, the effects of Richardson and Hartmann numbers on heat and mass transfer in a three-dimensional lid-driven cubical cavity subjected to a uniform magnetic field are investigated numerically. The lid is maintained at constant high temperature and is moving downwards in the negative y-direction. The wall opposite to the lid is stationary and maintained at constant low temperature, and all other walls are kept adiabatic. Entropy generation is also calculated to investigate the nature of irreversibility in heat transfer inside the cavity. The computations are performed for the Richardson numbers 10 and 100, and Hartmann number in the… More >

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R.V. Reji, S. Anil Lal^†
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.27
Abstract DSMC simulation of re-entry of an object with shape and size close to that of ISRO’s Space Recovery Experiment (SRE) capsule has been analysed using the open-source tool dsmcFoam for three altitude conditions, viz. 85 km, 100 km and 115 km, and for three angles of attack, viz. 0 o , 20o&40o . The hypersonic free stream velocity of 8000 m/s and boundary surface temperature of 300 K have been used for the simulations. The variation of parameters such as surface heat flux, surface pressure, shear stress, slip velocity, temperature jump and integrals such as total heat transfer, pressure drag… More >

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P. Chandra Reddy¹, M.C. Raju^1,*, G.S.S. Raju², S.V.K. Varma³
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-11, 2016, DOI:10.5098/hmt.7.28
Abstract The present analysis is focused on free convective heat and mass transfer characteristics of magneto-nanofluid flow through a moving vertical plate in the presence of thermal radiation and thermal diffusion. The water-based nanofluid containing copper is taken into consideration. A uniform magnetic field is applied perpendicular to the plate. The governing equations are solved by applying finite difference method. Numerical results of the fluid velocity, temperature, concentration, shear stress, rate of heat transfer and rate of mass transfer are presented graphically for different values of the physical parameters encountered in the problem. It is noticed that the fluid velocity increases… More >

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S.V. Subhashini^a,* , Nancy Samuel^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.29
Abstract The aim of this paper is to present non-similar solutions of a steady laminar compressible boundary layer flow past a long thin circular cylinder including the effects of wall enthalpy and surface mass transfer. The governing equations along with the boundary conditions are first converted into dimensionless form by a non-similar transformation, and then the resulting system of coupled non-linear partial differential equations is solved by an implicit finite difference scheme in combination with the quasi-linearization technique. The increase in the value of power law variation of viscosity causes an increase in the boundary layer thicknesses of both the velocity… More >

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Niki Rezazadeh, Rezvan Abdi^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.30
Abstract This study investigates the heat transfer in the mode of natural convection from a pair of hot cylinders to a cold square enclosure. Effects of boundary conditions of the enclosure on the rate of heat transfer from a pair of isothermal hot cylinders are investigated at a Rayleigh number of 10⁵ . The cylinders are arranged in a horizontal array at the middle height of enclosure. The commercial software, Fluent (V.6.3.26), is utilized to solve the problem using the Finite Volume Method. The streamlines as well as isothermal lines of the problem are reported. Moreover, the local Nusselt number on… More >

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Dave Martin^a,b,† , Hicham Chaouki^a,b, Jean-Loup Robert^a, Donald Ziegler^c, Mario Fafard^a,b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.31
Abstract The two dimensional phase change problem was solved using the extended finite element method with a Lagrange formulation to apply the interface boundary condition. The Lagrange multiplier space is identical to the solution space and does not require stabilization. The solid-liquid interface velocity is determined by the jump in heat flux across the i nterface. Two methods to calculate the jump are used and c ompared. The first is based on an averaged temperature gradient near the interface. The second uses the Lagrange multiplier values to evaluate the jump. The Lagrange multiplier based approach was shown to be more robust… More >

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Odelu Ojjela^*, K. Pravin Kashyap, N. Naresh Kuma, Samir Kumar Das
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.32
Abstract This article presents an unsteady incompressible Upper Convected Maxwell (UCM) fluid flow with temperature dependent thermal conductivity between parallel porous plates which are maintained at different temperatures varying periodically with time. Assume that there is a periodic suction and injection at the upper and lower plates respectively. The governing partial differential equations are reduced to non linear ordinary differential equations by using similarity transformations and the solution is obtained using differential transform method. The effects of various fluid and geometric parameters on the velocity components, temperature distribution and skin friction are discussed in detail through graphs. More >

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Mohammad Hasan Khademi^a,*, Abbas Mozafari^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.33
Abstract An integral energy equation model is used to calculate the heat transfer coefficient/Nusselt number, thermal boundary layer thickness and temperature distribution in the turbulent boundary layer for forced convection over a smooth flat plate. The proposed model is based on two polynomial temperature profiles in a thermal laminar sublayer as well as in a fully developed boundary layer and two integral energy equations. The performance of this new model is compared with the most commonly used semi-empirical correlations and the complex established models such as k-ε, k-ω, RSM, and a good agreement is achieved. More >

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Jacob Thottathil Varghese^a,*, Sat Ghosh^a,b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.34
Abstract Nature has its own astonishing capabilities to cleanse polluted environment. Living green drapes on buildings look elegant providing sustainable solutions in congested metropolises. VIT University promotes green values within the country. The walls of a subway connecting the main campus and hostel premises are draped with Vernonia elaeagnifolia, which was found to be efficient in capturing vehicular pollution. An experimental study established deposition patterns of pollutants. Thereafter, diffusive uptake modelling elucidated the mechanistic details of mass transport through the plant tissues. It is expected that the results of this paper will promote the use of green facades within built environment. More >

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A. Zoubir^a , R. Agounoun^a,*, I. Kadiri^b, K. Sbai^a , M. Rahmoune^a
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.35
Abstract Boiling heat transfer process is important because it is a way to increase the flux density transmitted at low temperature differences. To quantify the thermal exchanges, we performed an experimental study of the nitrogen pool boiling, in transient conditions, on a horizontal brass ribbon for a fixed flux density. The results show that there is no break between the monophasic convection zone and the nucleated boiling region. In the nucleated boiling zone, the temperature variations are very small. We also note that the overheating required to trigger boiling increases with the time delay after the activation of nucleation sites. More >

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Xiaoqian Ma^a , Mo Yang^a,*, Yuwen Zhang^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.36
Abstract Combustion mechanism of a 300 MW pulverized coal boiler is analyzed and the optimization of the performance of the boiler is carried out. The flow field, temperature field, devolatilization, char combustion and CO generation in the boiler furnace under actual condition is obtained by using Fluent. Three methods to improve the efficiency of boiler combustion are proposed based on the pulverized coal combustion mechanism; their feasibilities are verified through numerical simulation and analysis. The three proposed methods to increase the combustion efficiency may give theoretical reference for air arrangement and combustion optimization of the same type of burners. More >

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Wubshet Ibrahim^a,∗, Bandari Shankar^b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.37
Abstract The Numerical analysis of magneto-hydrodynamics (MHD) boundary layer flow and heat transfer of incompressible, viscous and electrically conducting fluid is presented. The flow is due to continuously stretching permeable surface embedded in non-Darcian porous medium in the presence of transverse magnetic field, thermal radiation and non-uniform heat source/sink. The flow equations in the porous medium are governed by ForchheimerBrinkman extended Darcy model. A similarity transformation is used to transform partial differential equations into a coupled higher order non-linear ordinary differential equations. These equations are solved numerically using implicit finite difference scheme called Keller-Box method. The effects of the governing parameters… More >

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Shahirah Abu Bakara, Norihan Md. Arifin^a,*, Roslinda Nazar^b, Fadzilah Md. Ali^a, Ioan Pop^c
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.38
Abstract A mathematical model of forced convection boundary layer stagnation-point slip flow in Darcy-Forchheimer porous medium over a shrinking sheet is presentedin this paper. The governing partial differential equations are transformed into ordinary differential equation using self-similarity transformation which are then solved numerically with shooting method. A parametric study of the physical parameters involved in the problem is conducted and representative set of numerical results are presented through graphs and tables, and are discussed. More >

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Etim S. Udoetok^*
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-5, 2016, DOI:10.5098/hmt.7.39
Abstract The radiation of heat by a hot body of gas is studied and a Stefan-Boltzmann kind of equation is developed. The proposed gas radiation equation is used to estimate the volumetric total emissivity of gas. The proposed total emissivity highlights the characteristics observed in published charts. The proposed gas radiation model requires the estimation of photon heat capacity from experimental data. Accurate estimation of total gas emission is very useful in applications involving combustion. Ideal gas and constant specific heats assumptions were used in the analysis for simplification. More >

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Dave Martin^a,b,† , Hicham Chaouki^a,b, Jean-Loup Robert^a, Donald Ziegler^c, Mario Fafard^a,b
Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-11, 2016, DOI:10.5098/hmt.7.40
Abstract A two phase model for two-dimensional solidification problems with variable densities was developed by coupling the Stefan problem with the Stokes problem and applying a mass conserving velocity condition on the phase change interface. The extended finite element method (XFEM) was used to capture the strong discontinuity of the velocity and pressure as well as the jump in heat flux at the i nterface. The melting temperature and velocity condition were imposed on the interface using a Lagrange multiplier and the penalization method, respectively. The resulting formulations were then coupled using a fixed point iteration a lgorithm. Three examples were… More >

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