Study Of High Performance, High Compression Ratio Pressure Recovery System For Chemical Laser

Pressure recovery system(PRS) is one of the key techniques for the high energy chemical lasers(HECL). In this paper, the high performance, high compression-ratio PRS and its sub-systems are intensively and deeply investigated through plenty of efforts in theoretical analysis , numerical simulation and experiments. A lot of important achievements have been made.Firstly, the up-to-date state of the high energy chemical laser weapon systems in the world is introduced and the development trend is viewed. The requirement to develop the high performance, high compression-ratio PRS is put forward. Secondly, the one-dimensional theoretical models of supersonic ejectors are developed. Based on it , the performances of all kinds of supersonic ejectors are compared and the effects of variety of input parameters on the performances of supersonic ejectors are discussed. The conclusion is reached, that the design scheme of small ejecting coefficient, high ejecting Mach-number, combustion-gas driving should be adopted to develop high performance, high compression-ratio PRS. Thirdly, the method of computational fluid dynamics is used to numerically solve the flow-field of the annular supersonic ejector with or without a second flow. Under different conditions, the flow mechanism of the annular supersonic ejector is observed. And the effects of different parameters on the performance of the supersonic ejector is discussed. Then the starting performance of the annular supersonic ejector is studied through a lot of "cold tests" (air driving) and "hot tests"(combustion-gas driving). Under the condition of high ejecting Mach-number, the discipline of the starting performance of the annular supersonic ejector is learned and compared with that of the center supersonic ejector. During the time, the gas-generator is developed successfully. After that, the one-stage PRS is connected with the chemical laser system to test cooperation of thetwo systems. Tests show that the ejecting capacity of the one-stage PRS is unable to fulfil the exhaust requkement of the chemical laser system, and that the starting process of the cavity and the diffuser is not thorough and the cavity pressure is too high, with the power output of the laser decreasing sharply. Then, based on the achievements of the one-stage PRS, a "subsonic-supersonic" two-stage PRS is developed and a lot of tests are made. The two-stage PRS is improved on and an advanced "supersonic-supersonic" two-stage PRS is creatively achieved. By using this two-stage PRS in the united test, the power output of the laser reach the output level when exhausting into vacuum tank. Finally, the optimal design of the multi-module diffuser is discussed through numerical simulation. And the optimal scheme of the multi-module difiuser is found out.