Brake disc temperature prediction in fade test using Computational Fluid Dynamics aero-thermal simulation

The Brake fade test is one of the critical validation activities during brake sizing in new project development. The size of the brake disc is designed according to the satisfaction of severe braking applications such as downhill, city traffic with heating and cooling cycle. During braking, the vehicle’s kinetic energy is converted to thermal energy which is absorbed by both disc rotor and brake pad. For cast iron rotors coupled with organic/semi-metallic pads the coefficient of friction may be dropped to as low as 0.2 beyond 350ºC, resulting in brake fade. This highlights the need for thermal performance evaluation of disc rotors. The rotor temperature also has a greater impact on the wear and tear of the brake pad material which directly affects the frequency of the service or replacement. The brake disc thermal performance is evaluated by repeated braking and cooling cycles which helps the brake disc achieve thermal equilibrium. Evaluating heat generation and dissipation characteristics in this phase would help us determine maximum temperature of rotor for all vehicle driving conditions. In this work, an attempt has been made to predict the temperature of the brake disc for light passenger vehicles with a standalone brake disc and vehicle level Computational Fluid Dynamics (CFD) simulation. Also, to further establish a good correlation both test track and vehicle level CFD results are compared with an analytical solution given by Rudolf Limpert. The CFD results shows a 97% correlation with vehicle level physical test.