Comparison between water and liquid nitrogen pressure surge experiments to analyze cavitation induced noise growth

Abstract

Water hammer phenomena play a major role in the design of rocket engine feed line systems. High amplitude pressure waves, generated by rapidly closing a valve to stop the chill down process or shut down the engine, can lead to acoustic cavitation inside the fuel delivery system. Since most liquid rocket engines are run by cryogenic fluids, but experiments with water need much less effort, it is of interest to understand the differences between the behavior of these fluids in rocket engine feed line systems. For that, several water and liquid nitrogen hammer tests have been performed at the Fluid Transient Test Facility (FTTF) at DLR Lampoldshausen. The aim of this paper specifically is to compare the grow rates of noise due to acoustic cavitation in order to make a statement about using water as a replacement fluid for cryogenic fluids.