Numerical study of a rotating liquid jet impingement cooling system

Abstract

The circular, liquid jet impingement provides a convenient way of cooling surfaces. To effectively cool the critical components inside the electric motors, a rotating jet impingement cooling system is proposed. The working liquid used for jet impingement is the automatic transmission fluid, which is insulating and readily available in most vehicles. The jet impingement system consists of a rotating pipe with two nozzles and a cylindrical target surface. It provides the direct and uniform cooling of the target surface with simultaneous lubrication. To evaluate the performance of the developed jet impingement cooling system, the numerical simulations with a uniform temperature target surface and two stable, unsubmerged, single phase jets are investigated. The commercial code is used to determine the heat removal performance. The validation of the numerical model is conducted by comparing with the empirical formula and the experimental measurements from the literature. The parametric studies considering the effects of the Reynolds number, the pipe rotation speeds and the fluid properties on the jet impingement cooling performance are investigated. Furthermore, a correlation of the average Nusselt number, the Reynolds number, and the pipe rotation speed is derived.