CFD design analysis of ventilated disc brakes

This thesis reports the numerical investigation of the automotive ventilated disc brake rotor. Disc brakes operate on the principle of friction by converting kinetic energy into heat energy. The main objective of a disc brake rotor is to store this heat energy and dissipate it as soon as possible. This work is carried out in a area where there is very limited understanding. Commercial CFD code FLUENT was used for carrying out the simulations with the rotor rotating in still air. Only one passage and blade were simulated as all the rotor passages were identical. Uniform temperatures were used on the rotor to simulate the braking condition. Sixteen different blade angle sets were simulated and the range of blade angles having the best aero-thermal performance were identified using mass flow rate, rate of heat dissipation and temperature uniformity as performance metrics. The effect of rotational speed and rotor temperature (corresponding to various braking conditions) on the aero-thermal performance was evaluated. The rotor speed and temperature were observed to have significant effect on the rotor performance. The number of blades in the ventilated disc brake rotor was also varied and was observed to have an impact on the aero-thermal performance of the disc brake rotor. Detailed design changes like inlet chamfer, blade leading edge rounding, and variable thickness blade and passage aspect ratio were incorporated. All these changes did have an effect on the aero-thermal performance of the disc brake rotor. The inlet chamfer and the leading edge rounding improved both the rate of heat transfer and the temperature uniformity. The variable thickness blade and the lower aspect ratio passage improved the temperature uniformity of the rotor.