TIME-DEPENDENT CALCULATION PROCEDURE FOR FULLY DEVELOPED AND DEVELOPING FLOW AND HEAT TRANSFER IN LOUVERED FIN GEOMETRIES

Abstract

Previous studies by Zhang et al. \\[1, 2], have shown the importance of including unsteady effects in the numerical simulation of air-side flow and heat transfer in compact heat exchangers. In this paper we describe a computer program for the time accurate flow and heat transfer calculations in an array of louvered fins. Preliminary calculations, ranging from the low Reynolds number laminar to the transitional regime, are performed for both fully developed and developing flow and heat transfer. The results capture the ''duct'' flow and ''louver directed'' flow regimes observed in earlier flow visualization studies. Preliminary results of spatial propagation of transition from steady to unsteady in a multilouvered fin array are also presented. In the transitional regime the effect of large-scale vorticity on heat transfer is captured with clarity. In view of the difficulties associated with detailed experimental flow and heat transfer measurements, the current computer program provides a powerful tool for understanding the fundamental flow structure and its effect on heat transfer in louvered fin heat exchangers.