Experimental Study On Natural Precooling Cycle Of Cryogenic Liquid Rocket

With the development of rocket technique and increasing requirement of large-power launch vehicle, the cryogenic propellant with higher specific impulse is applied more and more widely. Precooling technique is the key part of the prestart process of cryogenic liquid rocket. Comparing to the direct drain cool-down process used in China, the natural precooling cycle, which may save the propellant of the precooling, simplify the prestart program, delay the ignition of the rocket and be more safe in the process of precooling as well is employed in this paper.Based on the review of the historical developments of the precooling technology and the prospective applications, the present work focuses on the following sections:The simulation model, which is about a quarter of the real rocket precooling structure in volume, is created with similarity theory. The simulated experiment structure as well as measurement system and the operating procedure are introduced in this paper. Some modeling experiments have been processed, in both of the atmospheric pressure and the pressurized pressure. The conclusion can be referred to in the further experiment.The gas-phase inlet, the outlet of the reflux pipe is at above the liquid surface in the cryogenic tank, is presented. Comparing to the liquid-phase manner that the outlet of the reflux pipe is below the liquid surface in the tank, the cool-down cycle may last longer and the prestart program may be more simple in using the gas-phase inlet manner. The geysering problem which exists during the cool-down process and is harmful for the recirculation, should be solved in the application.