Role of vane configuration on the heat dissipation performance of ventilated brake discs

This study reports on the effects of vane outlet angle on thermo-fluidic characteristics of curved vane brake discs via validated numerical models. Three vane outlet angles (45°, 90° and 135°) are considered. For a given rotational speed within the operating range of 200-1000 rpm, results show that increasing the outlet angle from 45° to 135° enhances the overall cooling performance by up to 16%. It is found that the increasing outlet angle enhances circumferential pressure difference, which intensifies secondary flow perpendicular to the mainstream and hence evidently enhances local heat transfer on inner disc surface. Further, the increase of outlet angle results in stronger flow impingement on pressure sides of the vanes and hence enhances local heat transfer. However, severe flow separation endows the brake disc having the outlet angle of 90° with the poorest heat transfer on suction sides of the vanes while those for the others are similar. In addition, local heat transfer variation on rubbing surface, inner rim surface and outer rim surface due to the variation of outlet angle has negligible effect on overall cooling performance. Comprehensive heat transfer enhancement mechanisms clarified in the present study are helpful to motivate further improved designs.