热负荷及给水压力对水升华器启动和使用策略影响

Influences of heat load and feed water pressure on the start-up and operation strategy of sublimator

热负荷、给水压力等参数的匹配设计,对水升华器启动及运行过程中内部气-固-液相变界面的位置具有重要影响,从而影响其运行稳定性和使用策略。开展了水升华器分别在低热负荷低给水压力、高热负荷高给水压力工况下的启动试验研究,及水升华器在低热负荷低给水压力下启动运行至稳定后调整为高热负荷高给水压力运行的响应特性研究。阐明了热负荷及给水压力对水升华器启动和稳定运行策略的影响。试验结果表明:水升华器在较高热负荷及较高给水压力工况下启动,可以在更短时间内建立稳定状态,但发生"击穿"风险大;水升华器需在高热负荷、高给水压力下运行时,采用在低热负荷、低给水压力下启动,然后在高热负荷和高给水压力下运行的方式,可以减小启动过程的"击穿"风险,且不影响其稳态散热能力。

Heat load,feed water pressure and other factors influence the vapor-solid-liquid phase change interfaces during the start-up and work processes,and this will affect sublimator＇s work stability and operation strategy.Experiments on sublimator start-up with both low thermal load and low feed water pressure,and start-up with both high thermal load and high feed water pressure conditions were carried out to study the Influences of heat load and feed water pressure on the start-up and steady-state work performance of sublimator.At the same time,a two-stepexperiment on sublimator was also carried out and the temperature responses of sublimator were tested.Start-up sublimator with low heat load and low feed water pressure achieved a steady state at first,and then both the thermal load and feed water pressure were increased to a large value.The experimental results revealed that：1）Sublimator start-up with high thermal load and high feed water pressure reaches the steady-state in a shorter time,but this will increase the risk of breakthrough in start-up process.2）Due to the advanced self-adjust capability of the liquidsolid-gas interface location in sublimator,a new balance will be established quickly.This indicates that the risk of breakthrough can be decreased through starting the sublimator in low thermal load and low feed water pressure.Increasing the thermal load and feed water pressure after it reaches the steady state to decrease the risk of ＂breakthrough＂,it will not influence the heat rejection performance.