3D numerical investigation of trans-critical heat transfer enhancement in regeneration cooling channel with crescent rib

In this study, a numerical simulation of the trans-critical flow and heat transfer performance of n-decane in a regenerative cooling microrib structure channel is conducted. The shear stress transfer k-omega numerical model is used to compare the heat transfer enhancement mechanism between straight and crescent ribs to improve heat transfer deterioration in a smooth channel. Within the specific dimensions and operative conditions of the test case, the results demonstrate that the average temperature in a channel with crescent ribs was 70 K less than one with rectangular ribs, and the average Nusselt number in a channel with crescent ribs was 50 greater than one with rectangular ribs. When compared with the rectangular rib channel, the thermal performance in the crescent rib channel increased by 59.1%-66.4%, and the overall heat transfer performance increased by 18.3%-25.9%. Saw-tooth distribution was observed along the rib channel, breaking the thermal boundary layer and avoiding heat transfer deterioration. Two spanwise vortices produced by the crescent ribs enhanced the flow mixing and turbulence kinetic energy transport near the sidewall region, which is a significant reason for the superior thermal performance of the crescent rib channel.