Experimental and numerical investigations on the thermal performance over corrugated surfaces with different wave shapes induced by piezoelectric fan

Abstract

In this paper, the thermal performance of the corrugated surfaces cooled with a piezoelectric fan was studied. A total of 25 corrugated surfaces with different wave shapes have been tested under different Re and gap heights ( G). The results showed that only the corrugated surface with the A/ WPF of 0.167 and T/ WPF of 0.533 produces the highest Nuarea values for all conditions, which is approximately 50% higher than that of a flat surface. It is confirmed that the corrugated shape is not only conducive to promoting the development of the vortex structure but also beneficial to increase the effective heat transfer area so that the overall heat transfer is optimal. An empirical correlation for estimating Nuarea on the hot corrugated surfaces was developed which has a mean absolute deviation of 11.0% and a mean relative deviation of 0.2%, predicting 75.9% of the entire database within a ±20% band. In addition, a corresponding simulation on the flow field revealed that the gap distance between adjacent wave crests is the key to balance the increasing effective heat transfer area and promoting the development of the vortex structure.