Effect of a Surface Film on the Surface Temperature of a Rotating Cylinder

Abstract

Solution to the steady heat conduction problem of a rotating layered cylinder is presented. The governing differential equations (for the film and the substrate) are solved by using an integral transform technique. It is shown that the presence of a surface film measured in micrometers can substantially change the level of the surface temperature. The effect of the surface film on the surface temperature depends on: respective thermal properties of the film and the substrate; relative surface speed; heat source (contact) size; and surface film thickness. However, the range in which the effect of the film on the surface temperature is dependent on these parameters is limited. Outside this range (i.e., thin film/low speed or thick film/high speed) the surface temperature rise is determined by the thermal properties of the substrate, or by the properties of the film alone, respectively. Hence, outside this range, a further change in the film thickness does not influence the surface temperature rise. Dimensionless plots showing the change in surface temperature rise as a function of material thermal properties, surface speed, heat source size, and film thickness are presented. Behavior for specific material combinations are also presented. The present information can be utilized to predict the layer effect on the partition of heat between the layered cylinders.