Experimental Study And Theoretical Analysis Method Investigation On Natural Circulation Precooling Of Cryogenic Propellant Rocket Engine System

In order to convey the cryogenic fluids safely and efficiently in a feeding and transferring system of rocket engine, the precooling of the cryogenic pump system is of necessity and much importance. The current method for precooling is "draining cooling". This method not only wastes cryogenic fuel, but also causes safety problem. It is necessary to develop new type of precooling method, so the natural circulation cooling system is introduced.The paper firstly reviews the history and developments of the research and application on kinds of precooling methods recently adopted. Then, the paper lays emphasis on the experimental investigation of natural circulation precooling. Meanwhile, theoretical analyzing methods concerning with precooling are discussed. The paper also introduces a new analyzing method based on the comparison with the natural circulation boiler. We list main investigation as follows:1. Theoretical study on the natural circulation precooling involves complicated two-phase fluid flow and heat transfer. The paper discusses several typical analyzing methods concerned with precooling, and also introduces a new analyzing method based on the comparison with the natural circulation boiler.2. We design and build up cryogenic fluid natural circulation precooling system apparatus, including novel gas-phase inlet configuration.3. A number of test parameters of insulation, position of reflux pipe inlet arrangemts, injection etc. are explored in the experiment. The experimental results demonstrate that the natural circulation is an efficient way to precool the pump system and maintain it at cryogenic temperatures.In the end, the phenomena and problem in the experiment are discussed in the paper as well as suggestion on the further experimental investigation. The summary of the thesis is also given.