Local Heat Transfer Distributions Within a Rotating Pin-Finned Brake Disk

Abstract

This study presents local temperature and heat transfer coefficient distributions obtained experimentally on the internal surfaces of a rotating pin-finned brake rotor at realistic rotation speeds for braking (i.e., N = 100–300 rpm). To this end, the thermochromic liquid crystal technique in a rotating reference frame was employed. The results demonstrate that the bulk airflow within the ventilated channel of a rotating disk follows a predominantly backward sweeping inline-like path between the pin fins. Internal local heat transfer is distributed nonuniformly on both inboard and outboard surfaces, with twice higher average cooling from the outboard surface than the inboard surface: this possibly exacerbates the thermal stresses, which leads to thermal distortion of the rotor (i.e., coning).