A new experimental method to study the convective heat transfer characteristics of the interior passages of ventilated disc brakes

Abstract

Vehicle braking systems use sliding friction between discs and pads to convert large amounts of kinetic energy into heat. Thus, sufficient cooling of disc brakes is needed. Convective heat transfer is an efficient way to cool disc brakes and prevent very high temperatures. To enhance convective heat transfer, ventilated disc brakes are commonly used. Therefore, the heat transfer characteristics of the internal passages of ventilated discs are of special interest. This paper describes a new experimental method to study the convective heat transfer characteristics of the interior passages of ventilated disc brakes, in which a wheel rolled a ventilated disc with tapered radial vanes on a circular track to simulate the real working conditions of a ventilated disc brake. The naphthalene sublimation method was used to obtain convective heat transfer characteristics by the heat/mass transfer analogy principle. Different data reduction methods were used to present the experimental results. The correlations among the Nusselt number, Reynolds number and other geometric parameters of the tapered radial vanes are reported in this paper. The results indicate that the heat transfer coefficient has a close relationship with Coriolis acceleration. Thus, this paper reports a correlation between Coriolis acceleration and the convective heat transfer coefficient, which can be used to extend the results obtained by the tested discs to realistic cases.