Non-Boussinesq laminar mixed convection in a non-isothermal fin array

Abstract

A numerical simulation of laminar mixed convection in a shrouded vertical non-isothermal fin array has been investigated. Convective medium is treated as non-Boussinesq fluid with temperature dependent properties. Computations are performed for the parametric range: Grashof number = 5.3 × 104 to 2.3 × 106, Reynolds number = 100 to 2200, dimensionless fin spacing = 0.1 to 0.5, and dimensionless clearance = 0.0 to 0.4. Computations demonstrate substantial deviation in heat transfer, as high as 18%, resulting from variable property non-Boussinesq fluid flow over non-isothermal fin compared to constant property Boussinesq fluid flow over isothermal fin. Optimum heat transfer coefficient is found to exist in a range of fin height from 0.04 m to 0.05 m, while dimensionless optimum fin spacing lies in a range from 0.2 to 0.3. Finally, induced natural convection velocity component and overall Nusselt number are well correlated with the governing parameters of the problem.