Airfoil-shaped self-agitator for convective heat transfer enhancement

A novel airfoil-shaped self-agitator is developed for airside heat transfer enhancement within rectangular heatsink channels. Due to fluid-structure interaction, the airfoil-shaped self-agitator oscillates and generates vortices that improve mixing within the channel and thus improve the heat transfer. The fluid-structure interaction is simulated with the fully coupled method of remeshing. Numerical results show that the self-agitator can generate out-of-phase heaving and rotating motions to enhance heat transfer by 27% without additional power costs and the Nusselt number can be improved by 53% at the same Reynolds number. To investigate the fundamental aspects of the convective heat transfer enhancement with vortex generation, modal analysis is performed for the vorticity and temperature fields with dynamic modal decomposition. Instantaneous results can be constructed with steady mode and six dominant unsteady modes, while the steady mode results can be used to predict the average thermal performance. A prototype of the self-agitator is fabricated and tested experimentally for concept demonstration and validation. The experimental results show the self-agitator can improve the air-side thermal performance in the rectangular channel significantly without additional pumping power.