Thermal Analysis in Electromagnetic Rail Launcher Taking Friction Heat into Account under Active Cooling Condition

A high-efficiency thermal management system is one of the key points in the practical application of electromagnetic rail launcher (ERL). In this paper, the thermal characteristics in ERL with the section of rectangle, convex, and concave rails by active cooling under different friction coefficient condition are investigated. By two cooling approaches, at two launch rates, with four friction coefficients, peak temperature in convex rails at the same moment is minimum in three types rails. Joule heat dominates in three shapes rail by channel or surface/channel cooling approach, but friction heat is a nonnegligible part under multiple launching mode. The spatial and temporal distribution features of peak temperature of three shapes rail with different friction coefficient under active cooling condition are compared. The mathematical relations between friction coefficient, time and temperature rising caused by friction at pulse end time and shot end moment in ERL with the three types rail are obtained, respectively. In terms of obtaining lower maximal temperature in rail, the ERL with convex rails is the best one.