Experimental study of the effect of temperature on the coefficient of restitution of steel balls impact to some industrial metal sheets at elevated temperatures

In the fluidized beds used for drying or heating particles, heat is mostly transferred to particles through their impact to the container hot walls. The aerosols impact to the extremely hot fuselage of spacecrafts entering the earth atmosphere is another instance of impact at high temperatures. Here, experimental data were acquired using drop test of steel balls on heated industrial metal sheets to study the effect of temperature on collisions coefficient of restitution (COR). There was a definite long range of 200 degrees C-700 degrees C for the steel sheet in which COR remained constant. Indeed, below200 degrees C, COR of impacts to the steel sheet decreased monotonically and beyond 700 degrees C, a definite fall was seen due to steel phase change. For copper and aluminum sheets, there were temperature ranges of constant and decreasing COR. Finally, it was found that CORs calculated from some theoretical models were in the same order as experimental data. (C) 2020 Elsevier B.V. All rights reserved.