A Monolithic Approach to Simulate the Cooling Behavior of Disk Brakes 2013-01-2046

In the present paper we introduce a monolithic CFD approach to simulate the cooling-down characteristics of disk brakes. To ensure a strong coupling between fluid and solid domain the overall transient thermal problem is solved within a single flow solver during the complete cooling-down process. We employ a fully implicit second order solution procedure.

The experimental configuration consists of an inertia dynamometer including a generic 17 inch vented front disk with caliper, dust shield, bearing and knuckle. The validation is carried out for three different air flow velocities, with and without dust shield. The temperature is monitored via two thermocouples embedded into outer and inner rotor cheeks. In order to quantify the cooling-down characteristics, regression analysis are conducted on the temperature curves. The obtained cooling coefficient serves as comparison between measurement and computation.

Within the proposed monolithic CFD approach the whole transient thermal problem considering radiation, convection and conduction is solved for the fluid and solid domain, simultaneously in the frame of one single flow solver (i.e. monolithic approach, no partitioned coupling). Employing moving mesh for the solid domain leads to a realistic rotational symmetric temperature distribution over the brake disk. We present graphs of total heat flux, radiation heat flux and heat transfer coefficient over time. The validation is conducted on the basis of measured and computed cooling coefficients considering three different air flow velocities and two dust shield configurations. An influence of starting temperature for the rotor has been also confirmed by experiments and simulations, respectively. The dynamometer test rig enables high repeatability without disturbances usually occurring in vehicle integrated brake corners.