Numerical predictions on heat transfer and flow characteristics in a straight channel with different geometric parameters wavy ribs

Abstract

A wavy rib is presented and its influences on the performance of a non-rotating straight channel are studied numerically. For each geometric parameter of wavy rib, the target surfaces are determined and the corresponding performance parameters are evaluated, to explore how wavy ribs affect channel heat transfer, especially the ribbed wall. Rib height (he = e − 3e), rib round radius (r = 0–5 mm), and rib angle (α = 20–55°) are the three key geometric parameters to study. The investigated Reynolds number is 25,000 and the channel aspect ratio is 1:1. The results indicate that three geometric parameters affect the channel performance by altering the diversion and obstruction of wavy ribs on cooling air. Among them, rib height is a dominant geometric parameter that determines the heat transfer improvement, while rib round radius and rib angle are mainly employed to reduce the friction loss. High rib height and large rib round radius, which can significantly increase heat transfer area and effectively decrease friction loss, respectively, are the basic features of high-performance wavy ribs. Meanwhile, the wavy ribs after optimal design perform better than 45° V-shaped ribs in heat transfer enhancement at the same friction penalty.