Stanford Shateyi

Frontiers in Heat and Mass Transfer, Vol.9, pp. 1-6, 2017, DOI:10.5098/hmt.9.7

Abstract The spectral relaxation method is employed to examine natural convective heat and mass transfer, MHD flow over a permeable moving vertical plate with convective boundary conditions in the presence of viscous dissipation, thermal radiation and chemical reaction. The governing partial differential equations were transformed into a system of nonlinear ordinary differential equations by using a similarity approach. The resultant dimensionless ordinary equations were numerically solved by employing an effective Relaxation spectral algorithm with Chebyshev scheme. The pertinent results are then displayed in tabular form and graphically More >

Patrick C. Doherty, Heather E. Dillon^† , Justin Roberts

Frontiers in Heat and Mass Transfer, Vol.9, pp. 1-6, 2017, DOI:10.5098/hmt.9.1

Abstract The onset of turbulence in natural convection systems is difficult to predict using traditional computational techniques. The flow patterns that occur before and after the onset of turbulence may be better understood with the help of visual techniques like Schlieren imaging. Schlieren imaging allows visualization of the density gradients of a fluid using collimated light and refractive properties. In this experiment, a device was designed to test the behavior of airflow with non-isothermal boundary conditions within a rectangular cavity. Previous computational fluid modeling suggested a period doubling route to chaos in a cavity with a high aspect ratio and free… More >

Walid Aich^a,c, Lioua Kolsi^a,d,*, Abdelkarim Aydi^e,f, Abdullah A.A.A Al-Rashed^b , Noureddine Ait Messaoudene^a , Mohamed Naceur Borjini^d

Frontiers in Heat and Mass Transfer, Vol.9, pp. 1-9, 2017, DOI:10.5098/hmt.9.8

Abstract Numerical study of double-diffusive natural convection flow and entropy generation in 3D trapezoidal solar distiller was performed using computational fluid dynamics (CFD). In this research the flow, provoked by the interaction of chemical species diffusions and the thermal energy, is assumed to be laminar. Using potential vector-vorticity formulation in its three-dimensional form, the governing equations are formulated and solved by the numerical methodology based on the finite volume method. The main objective is to analyze the effects of buoyancy ratio for opposed temperature and concentration gradients and to focus the attention on three-dimensional aspects and generated entropy. The occurring heat… 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 as Rayleigh number increases for… 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 maximized. 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 the role of non-uniform heating… 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 the radiation calculations, the radiosity-irradiation… More >

Mohammed A. Tashkandi^a , Abdelkarim Aydi^b,*

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-6, 2018, DOI:10.5098/hmt.11.27

Abstract In this work, a computational study of convective heat transfer in a hybrid CNT-Al2O3/water nanofluid cavity filled. The main considered parameters are the Rayleigh number and nanoparticles volume fraction. Results are presented in terms of flow structure, temperature field, and average Nusselt number. Since CNT and Al₂O₃ have different shapes to models are used to evaluate the effective thermal conductivity. It was found that both increasing Rayleigh number and nanoparticles volume fraction increase the heat transfer intensify the flow and affect the temperature field. Adding nanoparticles enhances the heat transfer due to the enhancement of the effective thermal conductivity. The… More >

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

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-12, 2018, DOI:10.5098/hmt.11.15

Abstract A systematic approach for the optimal positioning of multiple isothermal heat sources mounted on the walls of a side vented open cavity filled with natural air (Pr = 0.70) under natural convection and surface radiation is discussed. A numerical investigation is performed for the different possible cases with the two isothermal heat sources of equal dimensions mounted on the walls of the cavity. The geometrical parameters like the aspect ratio (A = 2), side vent ratio (W1 = 0.50) and side port ratio (W2 = 0.50) along with the most pertinent parameters like Rayleigh Number (10⁴ ≤ Ra ≤ 10⁷… More >

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 >