Investigating the impact of cooling configurations on heat transfer coefficient and friction coefficient under rotating state

Abstract

A comprehensive study was conducted to compare the heat transfer coefficients (HTC) of four different pin–fin structures in a rotating state. The HTC were evaluated within specific conditions: the inlet Reynolds number (Re) varied from 10,000 to 70,000, the rotation number (Ro) ranged from 0 to 1.0, the temperature ratio (TR) spanned 0.04 to 0.22, and the Buoyancy number (Buo) ranged 0 to 2.55. The diamond pin-fins channel exhibited optimal HTC performance, whereas the elliptical pin-fins channel exhibited the least HTC. Remarkably, the droplet pin-fins channel demonstrated enhanced cooling effects near the channel entrance compared to the circular pin-fins channel, but in the latter part of the channel, the circular pin-fins channel exhibited higher HTC. Overall, the circular and droplet pin-fins channels had lower HTC than the diamond pin-fins channel but surpassed the elliptical pin-fins channel. The incorporation of pin-fins increased the interaction area between the coolant and the surface, leading to enhanced turbulence and coolant blending, thereby improving HTC. The pin-fins structure design was instrumental in boosting HTC. Research findings indicated a gradual enhancement in heat transfer effectiveness as the pin-fins structure transitioned from elliptical to diamond. Moreover, the study analyzed the influence of TR and Re on HTC, unveiling the complex interplay among pin-fins structures, fluid dynamics, and heat transfer efficiency.