Open Access

ARTICLE

Emmanuel Maurice Arthur^*, Timothy Ayando, Yakubu Ibrahim Seini
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-10, 2015, DOI:10.5098/hmt.6.21
Abstract The combined effects of chemical reaction and viscous dissipation on hydromagnetic mixed convective flow towards a vertical plate embedded in a highly porous medium with radiation and internal heat generation has been examined. The governing boundary layer equations have been transformed to a two-point boundary value problem using a local similarity approach and solved numerically using the Newton Raphson shooting method alongside the Fourth-order Runge - Kutta algorithm. The effects of various embedded parameters on fluid velocity, temperature and concentration have been presented graphically whilst the skin friction coefficient and the rates of heat and More >

View

330

Download

225

Open Access

ARTICLE

Benjamin Lepers^a,∗, Thomas Seitz^a, Guido Link^a, John Jelonnek^a,b, Mark Zink^c
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.20
Abstract A compact 10 kW microwave applicator operating at 2.45 GHz for fast volumetric heating and thermal cracking of lignite briquettes has been successfully designed and tested. In this paper, the applicator design and construction are presented together with a sequentially coupled electromagnetic, thermal-fluid and mechanical Comsol model. In a first step, this model allows us to calculate the power density inside the lignite material and the temperature distribution in the applicator for different water flow rates. In a second step, the total stress due to the thermal dilatation, the internal pressure inside the ceramic and More >

View

439

Download

218

Open Access

ARTICLE

D. Srinivasacharya^a,*, A.J. Chamkha^b, O. Surender^a, A.M. Rashad^c,d
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-7, 2015, DOI:10.5098/hmt.6.19
Abstract The aim of the present article is to analyze the influence of thermal and mass stratification on natural convection heat and mass transfer over a porous vertical plate with uniform and constant wall temperature and concentration in porous medium. The Brinkman-Forchheimer based model is employed to describe the flow in the porous medium. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms by pseudo-similarity variables. The resulting system of nonlinear, coupled partial differential equations is then solved numerically. The influence of pertinent parameters on the dimensionless velocity, temperature, concentration, More >

View

308

Download

480

Open Access

ARTICLE

M. Umamaheswar^a, M. C. Raju^a,*, S. V. K. Varma^b
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-7, 2015, DOI:10.5098/hmt.6.18
Abstract An investigation is carried out to analyze the unsteady MHD free convection, heat and mass transfer flow of a Newtonian fluid past an infinite vertical porous plate with homogeneous chemical reaction and heat absorption/generation. A uniform magnetic field is applied perpendicular to the plate. The non-dimensional governing equations are solved numerically by using finite difference method. The effects of various parameters governing the flow on velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number are studied through graphs. It is noticed that velocity decreases with an increase in Magnetic field while it increases with More >

View

339

Download

201

Open Access

ARTICLE

Yaqing Liu^a,*, Jinyu Ma^b
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-5, 2015, DOI:10.5098/hmt.6.17
Abstract This paper presents an exact solution for the magnetohydrodynamic (MHD) flow of an incompressible generalized Oldroyd-B fluid due to an infinite accelerating plate. The fractional calculus approach is introduced to establish the constitutive relationship of the Oldroyd-B fluid. The solutions in terms of Fox H-function are obtained by using the Laplace transform. When N = 0 the solutions corresponds to the generalized Oldroyd-B fluids, while θ → 0 and λ → 0 describes the Maxwell fluid and the generalized second fluid, as limiting cases of our general results, respectively. More >

View

353

Download

203

Open Access

ARTICLE

Zhuohuan Hu^a,*, Lulu Wang^a, Hui Wang^b, Mo Yang^a
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-8, 2015, DOI:10.5098/hmt.6.16
Abstract A numerical investigation was conducted to study the heat transfer in an aircraft cabin and the effects of air distribution under different angle and inlet velocity conditions. The Reynolds-averaged Navier–Stokes equations and the low Reynolds number turbulence model were used to simulate the airflow in the cabin. Mathematical statistics was used to process the relevant data, and statistical results revealed that different inlet angles and velocities significantly affect air temperature and flow field. The study also determined a set of optimum matching inlet vane angles and inlet velocities that result in an environment which meets More >

View

391

Download

569

Open Access

ARTICLE

Rudra Kanta Deka^a, Ashish Paul^b,*, Nityajyoti Kalita^c
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-5, 2015, DOI:10.5098/hmt.6.15
Abstract A theoretical study of thermal radiation effects on unsteady MHD natural convection flow of an electrically conducting fluid past a vertical plate with variable temperature is considered. It is supposed that the temperature of the plate decays exponentially with time. Exact solutions to the nondimensionalised coupled linear partial differential equations representing the flow problem are obtained using Laplace transform technique. Effects of different physical parameters involved in the temperature and velocity profiles are investigated, shown graphically and discussed. Skin friction and Nusselt number are also derived and their variations with respect to the parameters are More >

View

359

Download

208

Open Access

ARTICLE

Hui Jiang^a,b, Daming Wu^a,b,c, Jian Zhuang^a,b,*, Ying Liu^a,b,c, Changqing Huang^a,b
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.14
Abstract A new type of metal-plastic composite heat radiator with hemispherical microstructure array was proposed in this paper. The influence of the geometrical parameters of the microstructure array, including size of the hemisphere, configuration of hemisphere, tilt angle of the radiator, thermal conductivity and radiation emissivity of the plastic, on the process of heat transfer under natural convection were numerically simulated. It was concluded that the metal-plastic composite heat radiator with hemispherical microstructure array had comparable heat transfer behaviors with those of metal heat radiator. So it is possible to replace metal heat radiator by such More >

View

353

Download

236

Open Access

ARTICLE

Withada Jedsadaratanachai^a, Amnart Boonloi^b,*
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-19, 2015, DOI:10.5098/hmt.6.13
Abstract Numerical investigations on flow topology, heat transfer behavior and thermal performance evaluation in a circular tube heat exchanger with the punched delta winglet vortex generators (PDWVG) inserted in the middle of the test section are presented. The effects of the flow attack angles that converging to the center of the tube; α = 0°, 5°, 10°, 15°, 20°, 25°, and flow directions; winglet tips pointing downstream and upstream, are investigated for the Reynolds numbers; Re = 100 – 2000. The finite volume method and SIMPLE algorithm are used for the current study. The results are presented… More >

View

332

Download

452

Open Access

ARTICLE

B. Rushi Kumar^* , T. Sravan Kumar, A .G Vijaya Kumar
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-9, 2015, DOI:10.5098/hmt.6.12
Abstract The objective of this study is to investigated thermal diffusion and radiation effects on unsteady free convection chemically reacting fluid flow past an accelerated infinite inclined plate with variable temperature and mass diffusion under the influence of uniform transverse magnetic field when the magnetic lines of force are fixed relative to the fluid or to the plate studied in two cases, (i) when magnetic field fixed relative to the fluid (K=0), (ii) and the magnetic field fixed relative to the plate (K=1) have been considered. A general exact solution of the dimensionless governing partial differential equation More >

View

311

Download

218

Open Access

ARTICLE

Biswajit De^*, Rajsekhar Panua
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.11
Abstract An incorporated arithmetical model has been urbanized and investigated for CFD replication of a solitary cylinder, four stroke, straight inoculation, compressed ignition diesel engine of 3.5 kW for in-cylinder combustion analysis and authenticated under engine simulations at full load functioning conditions with foundation fuel diesel and 10% JME (volume basis) blend with diesel at invariable speed of 1500 rpm. For advancing the exactness of the exertion, a number of sub models, such as species transport model explaining the actual biodiesel energy content and molecular structure as soon as fuel blend is initiated, spray break-up model, More >

View

314

Download

209

Open Access

ARTICLE

Junjie Chen^*, Xuhui Gao, Deguang Xu
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-13, 2015, DOI:10.5098/hmt.6.10
Abstract Effect of wall thermal conductivity on hydrogen self-ignition and hydrogen-assisted ignition of propane-air mixtures in different feeding modes from ambient cold-start conditions were investigated numerically with chemical kinetic model in Pt/γ-Al2O3 catalytic micro-combustors. For the steady and transient state, effect of wall thermal conductivity on self-ignition characteristics of lean hydrogen-air mixtures was presented, and hydrogenassisted combustion of propane-air mixtures was investigated numerically in the co-feed mode and the sequential feed mode. The computational results indicate the large thermal inertia of the micro-combustor solid structure leads to slow temperature dynamics, and transient response is dominated by… More >

View

389

Download

239

Open Access

ARTICLE

Makoto Shibahara^*
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-4, 2015, DOI:10.5098/hmt.6.9
Abstract Overall heat transfer coefficients of the heat exchanger inserted twisted plates for CO2 were measured. The overall heat transfer coefficients increased with mass flow rates of water at the same Reynolds number in the experiment. It is considered that the helically twisting fluid motions in the twisted heat exchanger were contributed to the heat transfer enhancements. More >

View

333

Download

192

Open Access

REVIEW

Srinath Ekkad^a,*, Je-Chin Han^b
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-14, 2015, DOI:10.5098/hmt.6.8
Abstract Improved film cooling hole geometries and effect of coolant density on film cooling have been a focus since the 1970s. One of the first studies on modifying hole exit to improve film cooling effectiveness and quantifying coolant density effect was from Prof. Goldstein’s group. This paper provides an overview of the development and implementation of hole exit geometries as well as coolant density study over the past few decades and the impact on future studies of advanced hole geometries under realistic engine-like coolant-to-mainstream density ratio conditions. This work is not intended to be a comprehensive More >

View

384

Download

237

Open Access

ARTICLE

M. Y. Abdollahzadeh Jamalabadi^*
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-13, 2015, DOI:10.5098/hmt.6.7
Abstract An analytical study of entropy generation in steady boundary layer flow, heat and mass transfer characteristic of 2D convective flow of a micro polar fluid over a stretching sheet embedded through a highly absorbing medium is performed. The governing equations are continuity, momentum boundary layer, micro rotation, and energy takes into account of Rosseland approximation for thermal radiation sources are solved analytically. The governing system of partial differential equations is first transformed into a system of non-linear ordinary differential equations using similarity transformation. The transformed equations are non-linear coupled differential equations which are then linearized More >

View

377

Download

242

Open Access

ARTICLE

R.R. Kairi^a, Ch. RamReddy^b,*
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-7, 2015, DOI:10.5098/hmt.6.6
Abstract In this paper, we investigated the influence of melting on mixed convection heat and mass transfer from the vertical flat plate in a non-Newtonian nanofluid saturated porous medium. The wall and the ambient medium are maintained at constant, but different, levels of temperature and concentration. The Ostwald–de Waele power-law model is used to characterize the non-Newtonian nanofluid behavior. A similarity solution for the transformed governing equations is obtained. The numerical computation is carried out for various values of the non-dimensional physical parameters. The variation of temperature, concentration, heat and mass transfer coefficients with the power-law More >

View

347

Download

234

Open Access

ARTICLE

Arafat A. Bhuiyan^a,c, M. Ruhul Amin^b, Jamal Naser^c, A. K. M. Sadrul Islam^a
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-11, 2015, DOI:10.5098/hmt.6.5
Abstract In this study, the effects of thermal and hydraulic characteristics of wavy fin and tube heat exchanger are investigated. Simulation has been carried out by a commercial computational fluid dynamics code, ANSYS CFX12.0. The main objective of this study is to investigate the flow characteristics in turbulent flow. Results are predicted for the turbulent flow regime (2100≤Re≤7000) and compared with author’s previous work for laminar (400 ≤Re≤1200) and transitional (1300≤Re≤2000) flow regime. Regarding turbulence, the k-ω model was used to predict the turbulent flow characteristics with 5% turbulence intensity. Predicted results were compared with the More >

View

389

Download

224

Open Access

ARTICLE

J. Srinivas^*, J. V. Ramana Murthy
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-11, 2015, DOI:10.5098/hmt.6.4
Abstract The paper aims the heat transfer analysis for the flow of two immiscible micropolar fluids inside a horizontal channel, by the first and second laws of thermodynamics under the action of an imposed transverse magnetic field. The plates of the channel are maintained at constant temperatures higher than that of the fluid. The flow region consists of two zones, the flow of the heavier fluid taking place in the lower zone. The condition of hyper-stick is taken on the plates and continuity of velocity, micro-rotation, temperature, heat flux, shear stress and couple stress are imposed More >

View

444

Download

222

Open Access

ARTICLE

Mitiku Daba^*, P. Devaraj, S. V. Subhashini
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.3
Abstract In the present study, we investigated a problem of steady laminar mixed convection flow over a vertically stretching sheet with partial slip under convective surface boundary condition. The governing partial differential equations of the boundary layer flow are reduced into a set of nonlinear ordinary differential equations using a suitable similarity transformations. The system of non linear ordinary differential equations are solved by the Keller box method. Velocity, temperature and heat transfer rate are analyzed by considering the important parameters: Prandtl number Pr, convective parameter ε, slip parameter K and mixed convection parameter λ on the More >

View

315

Download

271

Open Access

ARTICLE

Manoj Kr. Triveni^*, Dipak Sen, RajSekhar Panua
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-6, 2015, DOI:10.5098/hmt.6.2
Abstract A numerical investigation through laminar natural convection has been executed to illuminate the effect of curvature ratio in an arch enclosure filled with water. The left side wall of the cavity is maintained at a higher temperature than that of the right side wall while the other walls are kept insulated. The governing equations such as continuity, momentum and energy equation are solved by finite volume method. The effect of pertinent parameters such as curvature ratio (1≤ CR ≤ 1.5) and Rayleigh number (1×10⁴ ≤ Ra ≤ 1×10⁶) and) on heat transfer are calculated by commercial More >

View

311

Download

211

Open Access

ARTICLE

J. N. Chung^*, Kun Yuan
Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-7, 2015, DOI:10.5098/hmt.6.1
Abstract Chilldown or quenching is a complicated process that initiates the cryogenic fluid line transport, and it involves unsteady two-phase heat and mass transfer. To advance our understanding of this process, we have reviewed recent experimental investigations. The chilldown process can be generally divided into three regimes: film boiling, transition boiling and nucleate boiling, and each regime is associated with a different flow pattern and heat transfer mechanism. Under low flow rate conditions, it is concluded that the two-phase flow regime is dispersed flow in the film boiling regime. The dispersed liquid phase is in the More >

View

387

Download

226