Enhancement in Rejected Heat from Heat Sinks Using High Flexible Winglets with Large Deformation and Low Blockage Effect

This paper presents an original concept of using high flexible flapping vortex generator in a heat sink for airside heat transfer augmentation. The proposed thin winglet, made with an elastic sheet, is responsible for increasing the cooling rate and mixing quality performance in laminar convection airflow. This study focuses on the excessive bending of the flapping winglet and reducing its blockage effect and pressure drop. This novel concept is demonstrated using a numerical simulation of the flow field with a coupled Fluid-Solid-Interaction technique in transient conditions. The continuity, momentum, and energy equations for forced convection airflow are solved by the finite element method using the COMSOL Multi-physics. Numerical results reveal high amplitude for the flapping vortex generator while under a large deformation and bending. This behavior leads to flow mixing with a small blockage effect due to the deformed aerodynamic shape of the winglet. The present findings show that the high flexible winglet enhances the rejected heat by 100%, with a 33% decrease in pressure drop compared to the rigid vortex generator at the same air velocity.