Effect of Reynolds and Prandtl Numbers on Mixed Convection in an Obstructed Vented Cavity

Abstract

A numerical investigation is conducted to analyze the steady flow and thermal fields as well as heat transfer characteristics in a vented square cavity with a built-in heat conducting horizontal solid circular obstruction. Hydrodynamic behavior, thermal characteristics and heat transfer results are obtained by solving the couple of Navier-Stokes and energy equations by using a weighted residuals Finite element method. The computation was made for different Reynolds number, Prandtl number ranging from 50 to 200 and from 0.71 to 7.1 at the three different convective regimes. Three different regimes are observed with increasing Ri: forced convection (with negligible free convection), mixed convection (comparable free and forced convection) and free convection dominated region (with higher free convection). The results are presented to show the effects of the Reynolds number, Prandtl number on flow pattern, thermal field and heat transfer characteristics at the three convective regimes. It is found that the flow and thermal field strongly depend on the Reynolds number, Prandtl number as well as Richardson number. As the Reynolds number and Prandtl number increase, the heat transfer rate increases but average fluid temperature in the cavity and temperature at the cylinder center decrease at the three convective regimes.

Numerical Modeling of Mixed Convection Heat Transfer of Laminar Fluid in Rectangular Enclosure With Openings in the Side

“…add the effect of convection between the main node (P) and the neighboring nodes (E, W, N, S) as shown in Fig. (2). After that and by following the (SIMPLE Algorithm) procedure, where the continuity equation was reformulated as a pressurecorrection equation [10].…”

“…In a mixed convection, both natural convection and forced convection participate in the heat transfer process [1].Thermal buoyancy forces play a significant role in forced convection heat transfer when the velocity is relatively small and the temperature difference between the surface and the free stream is relatively large. The buoyancy force modifies the flow and the temperature fields and hence the heat transfer rate from the surface [2].Many theoretical as well as experimental studies have been made for either pure forced convection or pure free convection [3].Very little has been known about combined free and forced convection heat transfer. In reality, pure forced convection heat transfer seldom occurs since density is dependent on temperature.…”

Analysis of Combined Convection in an Open Cavity under Constant Heat Flux Boundary Conditions and Magnetic Field Using Finite Element Method

“…There is a big challenge on cooling of electronic equipments to enhance efficiency of these devices as indicated by Nasrin [1], Hsu and How [2], Kieno et al [3], House et al [4], Dong and Li [5]. A numerical investigation of mixed convection in a ventilated square cavity with a heat conducting horizontal solid circular cylinder has been performed by Rahman et al [6]. In rectangular cavities at different phase ratios, Gau et al [7] conducted mixed convection with moving isothermal side walls and constant flux as a heat source on the bottom wall.…”