| The neutral beam injector is a device for producing high energy charged particle beam and is neutralized,and finally injecting high energy neutral particle beam into the fracture device for heating plasma,driving plasma current.The vacuum system is an indispensable part of the NBI system components.As the nuclear fusion study is continuous,the requirements for the operating parameters of NBI continue to improve.Traditional external vacuum pump sets have completely unable to meet NBI’s demand for large speed.Compared with the low temperature cooling pump,the low temperature adsorption pump has typical advantages such as high limit vacuum and good stability,Therefore,China Fusion Engineering Test Reactor Negative ion based Neutral Beam Injector device verifies that the sample vacuum system selection specially designed built-in forced cooling low temperature adsorption pump is obviously the most suitable choice.Therefore,it is of great significance to build a pumping performance test platform to verify the pumping performance of the specially designed built-in forced-flow cooling cryogenic adsorption pump.The article first introduced the development history of nuclear fusion and the necessity of neutral beam injection heating for the nuclear fusion device EAST and the future China Fusion Engineering Experimental Reactor(CFETR).The current EAST NBI device was introduced to the future CFETR NNBI verification prototype.Then introduced the composition and structure of the CFETR NNBI verification prototype and its working principle.Through the description of the vacuum system pumping mechanism,the cryogenic adsorption pump and the cryogenic condensate pump are compared,highlighting that the cryogenic adsorption pump can pump the helium produced by the nuclear fusion reaction.The typical advantages such as high ultimate vacuum have laid the foundation for CFETR NNBI to verify the selection of prototype cryopumps.In order to verify whether the pumping speed,pumping capacity,and regeneration characteristics of the designed cryogenic adsorption pump meet the requirements of the CFETR NNBI verification prototype vacuum system,a special pumping performance test system was designed and constructed to comprehensively evaluate the performance of the cryogenic adsorption pump developed.Test research.The pumping performance test system includes a specially designed pumping speed test cover,air intake system,vacuum measurement system,auxiliary pumping system and temperature control system.The main body of the test system is a vacuum chamber composed of a cryogenic adsorption pump and a pumping speed test cover.In order to verify the rationality of the designed pumping performance test system,the vacuum chamber was drawn by the three-dimensional drawing software Solidworks,and used based on Monte Carlo methods Molflow software has carried out simulation analysis and experimental verification on the designed vacuum chamber structure.The results show that in the order of 10-4-10-2pa,the pressure distribution in the vacuum chamber gradually decreases along the movement direction of gas molecules,and with the increase of the intake air volume,the pressure in the vacuum chamber also increases,and the increasing trend is roughly linear.The relationship indicates that the pumping performance of the system is stable,thereby proving the rationality of the pumping performance test system.The research results of this paper provide strong support for the future CFETR NNBI to verify the performance evaluation of the prototype cryogenic adsorption pump and the further testing and research of the cryogenic adsorption pump pumping performance.Figure[31] table[8] reference[51]... |
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