This paper addresses the laminar boundary layer flow of selected binary gas mixtures along a heated flat plate. To form the binary gas mixtures, light helium (He) is the primary gas and the heavier secondary gases are nitrogen (N2), oxygen (O2), xenon (Xe), carbon dioxide (CO2), methane (CH4), tetrafluoromethane (CF4) and sulfur hexafluoride (SF6). The central objective in the work is to investigate the potential of this group of binary gas mixtures for heat transfer intensification. From fluid physics, two thermophysical properties: viscosity η and density ρ influence the fluid flow, whereas four thermophysical properties: viscosity η, thermal conductivity λ, density ρ, and heat capacity at constant pressure Cp affect the forced convective heat transfer. The heat transfer augmentation from the flat plate is pursued by stimulating the forced convection mode as a whole. In this regard, it became necessary to construct a specific correlation equation to handle binary gas mixtures owing Prandtl number Pr ∈ (0.1, 1). The rate of heat transfer Q between a heated plate and a cold fluid is calculated with: Qmix/B=λmix0.623ρmix0.500Cp,mix0.377ηmix0.123(1) If the surface area of the plate A and the temperature difference Tw–T∞ are specified, the only possible way for intensifying the rate of heat transfer Q is by enlarging the magnitude of the average heat transfer coefficient h. This is precisely the main goal to be pursued in the present paper. The average heat transfer coefficient h in laminar boundary layer flows of incompressible, viscous fluids along heated flat plates depends on the dimensionless fluid temperature gradient at the plate θ′(0). It is given by the Prandtl number function f (Pr).
Heat transfer coefficient in agitated vessel with perforated screw mixer.
