Heat dissipation optimization of ventilated brake disc recirculation zone based on NSGA-II algorithm

Abstract

The Brakes contact surface temperature rises sharply when vehicle braking by friction, so vehicles are generally equipped with ventilated brake discs for cooling. However, the recirculation zone in the ventilated brake disc passage severely blocks fluid flow. In order to improve the convective and heat dissipation performance of the ventilated brake disc, this paper aims to introduce an optimized slotted vane geometry to improve the heat dissipation performance of ventilated brake discs. Therefore, three structural parameters of slot width, slot inclination and number of vanes were selected as optimization variables, and the optimization objective was to maximize the mass flow rate and convection heat transfer coefficient. And then, combined with the RSM and NSGA-II for optimization. The results showed that the optimized slotted vanes effectively suppressed the recirculation zone in the flow passage and made the airflow distribution more uniform. The optimal characteristic parameters after optimization are N = 36,θ = 56.38°, H = 12.7 mm. The CFD calculation results are consistent with the experimental results, and the Nu error obtained is about 2.6%. Within the given speed range, compared with experimental data of the straight vane brake disc, the total heat dissipation rate of the optimized brake disc is increased by 9%, the heat dissipation rate in the channel was increased by 5.6%, and the pumping capacity is increased by 12%.