Hussein M. Jassim, Farooq H. Ali^* , Qusay R. Al-Amir, Hameed K. Hamzah, Salwan Obaid Waheed Khafaji

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-9, 2019, DOI:10.5098/hmt.12.22

Abstract This study is focused on the entropy generation of laminar natural convection inside a sinusoidal enclosure filled with air (Pr=0.71). The numerical investigation is performed for three shapes of inner cylinders (circle, square, and equilateral triangle) with the same area and different values of the Rayleigh number (10³-10⁶). Galerkin Finite Element Approach is utilized to solve the governing equations. The results showed that the entropy generations due to heat transfer, fluid friction and total entropy generation increase with increasing values of Rayleigh number, while the local Bejan number decreases. More >

Partner L. Ndlovu^a,b,∗, Raseelo J. Moitsheki^a,†

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-8, 2019, DOI:10.5098/hmt.12.7

Abstract In this article, the Differential Transform Method (DTM) is used to perform thermal analysis of natural convective and radiative heat transfer in moving porous fins of rectangular and exponential profiles. This study is performed using Darcy’s model to formulate the governing heat transfer equations. The effects of porosity parameter, irregular profile and other thermo-physical parameters, such as Peclet number and the radiation parameter are also analyzed. The results show that the fin rapidly dissipates heat to the surrounding temperature with an increase in the values of the porosity parameter and the dimensionless time parameter. The More >

Hasan Sh. Majdi^a , Ammar Abdulkadhim^b,* , Azher M. Abed^b

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-14, 2019, DOI:10.5098/hmt.12.2

Abstract Fluid flow and natural convection heat transfer in a parallelogram enclosure with an inner circular cylinder using Cu-water nanofluid are studied numerically. Dimensionless Navier-Stokes and energy equations are solved numerically using finite element method based two-dimensional flow and steady-state conditions. This study evaluates the effect of different concentrations of Cu-water nanofluids (0% to 6%) with different Rayleigh numbers 10³ ≤ Ra ≤ 10⁶ under isotherm wall temperatures. The effects of geometrical parameters of the parallelogram enclosure (inclination angle in range of 0 ≤ α ≤ 30 and location of inner circular cylinder -0.2 ≤ H ≤… More >

Chadwick D. Sevart^* , Theodore L. Bergman

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-18, 2019, DOI:10.5098/hmt.13.18

Abstract A design approach is proposed and demonstrated to identify desirable two-dimensional solid geometries, cooled by natural convection, that offer superior thermal performance in terms of reduced overall (conduction-convection) thermal resistance. The approach utilizes (i) heat transfer modeling in conjunction with (ii) various novel shape evolution rules. Predictions demonstrate the evolution of the solid shape and associated reduction of the overall thermal resistance. Parametric simulations reveal the dependence of the predicted solid shape on the evolution rule employed, the thermal conductivity of the solid material, and the strength of advection within the fluid. More >

Rafiq Manna^* , Patrick H. Oosthuizen

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-12, 2019, DOI:10.5098/hmt.13.7

Abstract Natural convective heat transfer from two-sided diagonally inclined square plates having various thicknesses has been numerically and experimentally investigated. The aim of this work is to determine the influence of the plate thickness and diagonal inclination angle on the heat transfer rate for various flow regimes. The mean heat transfer rate was numerically obtained using ANSYS FLUENT© and experimentally determined using the Lumped Capacity Method. The results indicate that the plate thickness does not have a significant influence on the heat transfer rate while the diagonal inclination angle significantly influences the heat transfer rate especially More >

H. Astuti^a, P. Sri^b, S. Kaprawi^a,†

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.3

Abstract The natural convection of the nanofluids from a vertical accelerated plate in the presence of the radiation flux and magnetic field is observed in this study. Initially, the plate with a temperature higher than the temperature of nanofluids is at rest and then it accelerates moving upward and then the wall temperature decreases. The governing unsteady equations are solved by the explicit method based on the forward finite difference. Three different types of water-based nanofluids containing copper Cu, aluminum oxide Al₂O₃ and titanium dioxide TiO₂ are taken into consideration. The hydrodynamic and thermal performance of the More >

Gang Qiu^a , Mo Yang^a,*, Jin Wang^b , Yuwen Zhang^c

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-8, 2018, DOI:10.5098/hmt.10.24

Abstract An unsteady numerical model for double-diffusive natural convection of low Prandtl number liquids with Soret and Dufour effects inside the horizontal cavity is developed. The thermosolutal model is solved numerically using the SIMPLE algorithm with QUICK scheme. The flow field, temperature and concentration distributions for different buoyancy ratios, Rayleigh numbers and aspect ratios under different Prandtl numbers are studied systematically. The results reveal that the flow structure develops from conduction-dominated to convection as buoyancy ratio increases under different Prandtl numbers. Heat transfer intensity keeps constant and mass transfer intensity grows slowly before a critical point More >

Saeed Zaidabadi Nezad, Mohammad Mehdi Keshtkar^*

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-7, 2018, DOI:10.5098/hmt.10.11

Abstract This work reports numerical optimization of natural convection in a square enclosure with local heating of the floor and symmetrical cooling of the sides. This analysis was done to optimize heat transfer from two semiconductors in a square electronic package. It became clear that the major part of entropy generation was due to irreversibility of heat transfer and a small amount of it was related to fluid friction. For heaters with equal power ratio, it is very unpleasant to place heaters near the middle plate of the enclosure, since peak temperatures and entropy generation are More >

Shantanu Dutta^* , Arup Kumar Biswas

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-12, 2018, DOI:10.5098/hmt.10.8

Abstract Industrial processes optimization for higher energy efficiency may be effectively carried out based on the thermodynamic approach of entropy generation minimization (EGM). This approach provides the key insights on how the available energy (exergy) is being destroyed during the process and the ways to minimize its destruction. In this study, EGM approach is implemented for the analysis of optimal thermal mixing and temperature uniformity due to natural convection in quadrantal cavity filled with porous medium for the material processing applications or for cooling of electrical equipments. Effect of the permeability of the porous medium and… More >

Ravi Shankar Prasad^a , S.N. Singh^b , Amit Kumar Gupta^c,*

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-15, 2018, DOI:10.5098/hmt.11.28

Abstract This paper presents the results of numerical analysis of steady laminar natural convection and surface radiation in the two dimensional partially right side open square cavity filled with natural air (Pr = 0.70) as the fluid medium. The cavity has left isothermal hot wall with top, bottom and right adiabatic walls. In the present study, the governing equations i.e. Navier-Stokes Equation in the stream function – vorticity form and Energy Equation are solved for a constant thermophysical property fluid under the Boussinesq approximation. For discretization of these equations, the finite volume technique is used. For More >