Mixed convection heat and mass transfer in inclined rectangular ducts

Abstract

A numerical study was made to investigate the laminar mixed convection heat and mass transfer in inclined rectangular ducts. Using the vorticity-velocity method, three-dimensional Navier-Stokes equations, the energy and concentration equations were solved simultaneously. Six independent parameters are introduced: Prandtl number Pr, mixed convection parameter ω, modified Rayleigh number Ra ∗ , buoyancy ratio N, aspect ratio γ and Schmidt number Sc. The numerical results, including the local friction factor ratio, local Nusselt and Sherwood numbers, are presented for species diffusion of interest in air ( Pr = 0.7) over a Schmidt number range of Sc = 0.2–2.0. In the study, the mixed convection parameter ω ranges from 0 to 200, while the modified Rayleigh numbers Ra ∗ are varied from 0 to 10 5 for the aspect ratios γ = 0.5, 1, and 2.0 with buoyancy ratios N ranging from −0.5 to 2.0. The results show that the buoyancy effects have a significant influence on the characteristics of fluid flow, heat and mass transfer. Additionally, the fRe (fRe) 0 , Nu and Sh are enhanced as the buoyancy force from species diffusion assists the thermal buoyancy force.