Quanfu Gao^a,b , Kun Zhang^a,b,*, Liang Bi Wang^a,b

Frontiers in Heat and Mass Transfer, Vol.14, No.1, pp. 1-10, 2020, DOI:10.5098/hmt.14.29

Abstract Detailed numerical analysis is presented for natural convection heat transfer in internally finned horizontal annuli. Governing equations are discretized using the finite volume method, and solved using SIMPLE algorithm with Quick scheme. The results show that the flow and heat transfer can reach steady state when the Rayleigh number is below 2×10⁴. When the Rayleigh number is greater than 3×10⁴ , two different types of numerical solutions under the same parameters can be obtained for different initial conditions. The critical Rayleigh numbers with two different initial conditions are different from steady to unsteady solutions. The oscillatory flow undergoes several bifurcations… More >

Zhiyun Wang^† , Zixuan Zhou, Mo Yang

Frontiers in Heat and Mass Transfer, Vol.14, No.1, pp. 1-7, 2020, DOI:10.5098/hmt.14.13

Abstract Double diffusive natural convection in an open cavity under the Soret and Dufour effect is simulated numerically. The influences of different Rayleigh numbers (range from 103 to 107), Lewis numbers (range from 0.5 to 8), buoyancy ratios (range from -5 to 5) and Soret and Dufour (range from 0 to 0.5) on the flow field, temperature and concentration distributions, as well as on the variation of the average Nusselt number and the average Sherwood number are investigated. The result shows that, when buoyancy ratios is -1, the average Nusselt number and the average Sherwood number reaches the minimum, namely the… More >

Saddam Atteyia Mohammad^*

Frontiers in Heat and Mass Transfer, Vol.14, No.1, pp. 1-10, 2020, DOI:10.5098/hmt.14.7

Abstract An analysis was performed to study the effects of variable viscosity on steady, laminar, hydromagnetic simultaneous heat and mass transfer by mixed convection flow along a vertical cylinder embedded in a non-Darcy porous medium. The analysis was performed for the case of power-law variations of both the surface temperature and concentration. The viscosity of the fluid is assumed to be an inverse linear function of temperature. Certain transformations were employed to transform the governing differential equations to non-similar form. The transformed equations were solved numerically by finite difference method. The entire regime of mixed convection was studied. From this study… More >

Mahmud H. Ali^a,* , Rawand E. Jalal^a

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-14, 2020, DOI:10.5098/hmt.15.27

Abstract In this work, natural convection in an adiabatic enclosure with openings induced by two isothermal hot cylinders is approached numerically. The study covers five different configurations of the enclosure as the number and locations of the inlet and outlet ports are varied for Rayleigh number (Ra) between 10⁴ and 10⁶ . Additionally, the study also analyzes the effects of varying the horizontal distance (S) between the cylinders along with their vertical locations () for dimensionless values of 0.4 to 0.3 and -0.2 to 0.2, respectively, at a constant Ra of 10⁶ . The outcomes show that the locations of the… More >

N. Govindaraj, A. K. Singh, Pankaj Shukla

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-8, 2020, DOI:10.5098/hmt.15.20

Abstract A numerical study of fluid flow over stretching sheet with temperature dependent properties has been performed induced by mixed convection. The significant variation of the Prandtl number and viscosity in the temperature is observed [see table 1]. Viscosity and Prandtl number are vary in inverse of the linear function. The physical problem modeled in the mathematical equations in dimension form, which is converted to the non-dimensional equations by applying similarity transformations and suitable boundary conditions. The mathematical modelling problem is transformed PDE’s are numerically solved using Quasilinearization technique and FDM. The current numerical data has been presented in terms of… More >

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-15, 2020, DOI:10.5098/hmt.15.13

Abstract Simulated examinations on convective heat transfer and flow topology in a square duct heat exchanger placed with wavy thin rib (WTR) are presented. The influences of WTR heights, pitch distances and flow directions on flow and heat transfer characteristics are investigated for the laminar flow regime at the inlet condition (Re = 100 – 2000). The finite volume method (SIMPLE algorithm) is picked to analyze the numerical problem. The numerical validations; grid independence and verification of the smooth duct, are presented. The simulated results of the heat exchanger duct placed with WTR are reported in terms of flow and heat… More >

Isam Mejbel Abed, Farooq H. Ali^* , Shaymaa Abdul Munem Sahib

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-9, 2020, DOI:10.5098/hmt.15.6

Abstract Forced and mixed convection in 2-D, steady state, laminar flow and heat transfer around sinusoidal corrugated circular cylinder are numerically studied. Finite Element of Galerkin approach is used to analyze continuity, momentum and energy equation at Reynolds number (Re = 01, 45, 100, 200), Richardson Number (Ri=0, 1, 2), corrugation number (G = ꚙ, 3, 4, 5, 10), amplitude values (λ= 0.1, 0.2, 0.3 and 0.6) for Prandtl number (Pr = 0.71). Results show the variation of corrugation number G and amplitude value λ have important effect on the streamline , isothermal lines, local and average Nusselt number around the… More >

Rabha Khatyr^*, Jaafar Khalid Naciri

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-11, 2020, DOI:10.5098/hmt.15.5

Abstract The present study focuses on the effects of viscous dissipation and axial heat conduction on the asymptotic behavior of the laminar forced convection in a circular duct for a Herschel-Bulkley fluid with variable wall heat flux. Analytical asymptotic solutions are presented for the case of axial variations of the wall heat flux, with finite non-vanishing values at infinity along the flow direction. The asymptotic bulk and mixing Nusselt numbers and the asymptotic bulk and mixing temperature distributions are evaluated analytically in the case of axially variable wall heat flux for which polynomial and logarithmic functions are considered as examples. It… More >

D. Santhi Kumari^a,*, Venkata Subrahmanyam Sajja^a, P. M. Kishore^b,†

Frontiers in Heat and Mass Transfer, Vol.16, No.1, pp. 1-10, 2021, DOI:10.5098/hmt.16.24

Abstract This study attempts to explore a qualitative analysis of the effects of Soret on an unsteady magnetohydrodynamics free convection flow of a chemically reacting incompressible fluid past an infinite vertical plate embedded in a porous medium taking the source of heat and thermal radiation into account as well as viscous dissipation. The central equations are scrupulously converted into sets of coupled nonlinear partial differential equations for providing logical solutions. The method of Galerkin finite element is used considering appropriate boundary conditions for diverse physical metrics and then numerically analyzed employing MATLAB. A significant change in velocity, temperature, concentration profiles is… More >

N.Vijaya^a,* , P. Krishna Jyothi^b, A. Anupama^c, R. Leelavathi^d, K. Ambica^e

Frontiers in Heat and Mass Transfer, Vol.17, No.1, pp. 1-8, 2021, DOI:10.5098/hmt.17.23

Abstract The main intention of this study is to explore Maxwell fluid under the influence of thermophoresis and buoyancy forces induced by exponentially stretching sheet under chemical reaction. Cattaneo –Christov heat flux model is used to explore heat and mass characteristics with variable magnetic field, and chemical reaction. Variables of similarity were induced to transmute partial differential equations into dimensionless equations and are resolved numerically by elegant method bvp 4c. Behavior of various critical parameters on velocity, temperature and concentrations is graphically presented and discussed. Non Newtonian nature of the Maxwell fluid is clearly explored by the Maxwell parameter, it was… More >