Numerical simulation of steady and filling process of low temperature liquid propellants pipeline

摘要

Liquid hydrogen and liquid oxygen are widely used in the fields of the national defense, chemical industry and other advanced industries. Especially in the astronautics field, the transporta- tion process of low temperature liquid propellants becomes an important research task. For exmple, if the pre-cooling condition of the low temperature propellants of the engine to start up will not be reached, it will take longer pre-cooling time and more expenses to experiment. Further more after rocket engine startup, the pump of liquid hydrogen will be resulted in shutting down due to overspeed if there is the two phase ow. It is necessary to progress numerical simulation for the steady ow and pre-cooling process of liquid hydrogen/liquid oxygen transportation pipe by using the method of computational uid dynamics and numerical heat transmission. The main contents of the article in- cludes two aspects. Firstly, considering compressibility of liquid hydrogen/liquid oxygen, the SIMPLE method has been used to calculate 2-D steady state transportation, and finite difference method has been adopted to simulate 1-D heat transmission of the high vacuum multi-layers adiabatic structure. Flow field, temperature field and heat transmission have been calculated and analyzed, in order to optimize existing transportation pipe and reduce the loss of low temperature propellants. Secondly, using uid dynamics model of 1-D homogeneous balance state and heat transfer model covering main heat transfer work conditions in pre-cooling process, considering compressibility of low temperature propellants, pipe ow formula is calculated by finite volume method and 1-D non-steady state heat conduction formula of internal pipe-wall is calculated by finite difference method. The pre-cooling process of the test-bed system of rocket engine is calculated, simulative and experimental results are analyzed,and the results provide the evidences for the improvement of the engine system, test-bed system and the design of new system.