Experimental and numerical study of turbulent flow and thermal behavior of automotive brake disc under repetitive braking

The frictional brake system is the most safety critical equipment to decelerate or stop a vehicle. Thermal performance of the frictional region parts, disc and pads, necessitates to evaluate precisely in the design and test steps. In this study, a brake test setup was designed and fabricated with exactly the same braking components used in a common passenger vehicle as disc, pads, rim, tire, and dust shield to simulate the sequential braking. The local temperature on the disc and pads and the brake fluid pressure were measured. In addition, a three dimensional numerical model was designed to simulate the aerodynamics and thermal performance of the braking in detail. Finite element method was employed to simulate the frictional heat between the brake disc and the pads. The results showed that although the velocity of mainstream airflow reduces significantly into the rim, turbulent flow develops in the form of eddies of swirling airflow. Additionally, transient temperature distribution on the braking components was predicted. The cooling vanes in the brake disc have considerably enhanced the convection heat transfer. The amount of convective heat transfer on the inner radial vanes was more than 58% of the total amount of convective heat transfer.