A flapping vortex generator for heat transfer enhancement in a rectangular airside fin

Abstract

This paper presents a two-dimensional numerical study of a novel flapping vortex generator mounted on a heatsink fin for airside heat transfer enhancement. The proposed vortex generator is made with a thin elastic sheet bonded to the inner wall of the heatsink channel with an inclined angle. Our investigations are focused on the effects of the Young’s Modulus of the vortex generator on the oscillations of the elastic sheet, vorticity fields, and heat transfer performances. The results are compared with the heat transfer performances of conventional rigid agitators at two different flow velocities (Reynolds nunbers). Our numerical results demonstrate that the vortex generator with a Young’s Modulus of 1 MPa has the best performance among the other three choices and can enhance the rejected heat by 140% at the same velocity and 87% at the same total pumping power. The developed flapping vortex generator can improve the average Nusselt number by 200% compared with a clean channel with the same Reynolds number. Modal analysis is performed with transient temperature and vorticity results using dynamic modal decomposition where it is found that a steady modal behavior directly influences the thermal performance of the system. Furthermore, creating more discrete patterns near the boundaries of the steady mode in the vorticity field can enhance the internal convective heat transfer rate. The numerical results presented can help to guide the design of the flapping vortex generators in future high-performance airside fins.