Determination of Forced Convective Heat Transfer Coefficients on an Array of Discs

Abstract

Forced convection heat transfer due to airflow across an array of thin discs is encountered in various engineering applications. In this work, a three-dimensional steady Reynolds-Averaged Navier-Stokes computational fluid dynamics (CFD) simulation is performed to investigate the phenomenon at the surfaces of an array of discs. A computational grid comprising of a solid domain representing the array of discs and a fluid domain denoting the airflow is set up. A two-step solution procedure is employed whereby first the airflow across the discs is simulated till convergence and then the heat transfer is calculated. The temperature of the air before the array of discs, that of each surface of the discs, and the wall heat flux are monitored to calculate average convective heat transfer coefficients (CHTCs). The CFD model is validated using a wind tunnel experiment and it is shown that both are in close agreement with each other based on the surface temperatures and average CHTC predictions. The CHTCs are found to be significantly higher on the upwind face of the discs compared to the downwind side. Finally, based on the simulations, a correlation based on the non-dimensional average Nusselt number versus Reynolds and Prandtl numbers is derived.