Two‐dimensional‐numerical investigation on the influence of first rib distance from the entrance of channel on Nusselt number and pressure drop

Abstract

AbstractEnhancing the heat transfer coefficient in heat sinks can be achieved by surface modification techniques. Although the addition of ribs increases heat transfer capacity, it also increases pressure drop, lowering the channel's thermohydraulic performance (THP) factor. Rib research began a decade ago, with the majority of studies focusing on new rib designs or factors such as relative roughness pitch, relative roughness height, channel width, and channel height (geometric optimization) to improve THP. The goal of this study is to investigate the influence of the positioning of the first rib from the channel entrance on the Nusselt number, pressure drop, and THP factor with a simple design that could be manufactured easily. Three distinct rib designs are evaluated with rib positioning from the channel entrance, rib thickness, pitch, and Reynolds number as the parameters. It was found that the fluid starts settling up at the ribs as the ribs are moved closer to the channel entry point, thus increasing the pressure drop and reducing the fluid velocity. For the proposed design and dimensions, the Nusselt number increases by 3%–5%, and the pressure drop lowers by 4%–14% when the first rib is placed away from the channel entrance.