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 More >

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 More >

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 >

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 More >

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 More >

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 More >

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… More >

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 >

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 >

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 More >