To study the changes of the oxygen partial pressure and the total pressure in the pressurized cabin of manned spacecraft during cabin leaking,a simulation model of the air pressure control system was established.The effects of the pressurized cabin volume and the diameter of the leaking orifice on the changes of the oxygen partial pressure and the total pressure were analyzed with this model.The results showed that the time needed for the oxygen partial pressure and the total pressure to descend to the lower limit was shorter when the cabin volume was smaller or the diameter of the leaking orifice was bigger.The bigger the diameter of the leaking orifice,the higher the initial leaking flux,however,the descent of the rate of the leaking flux was also higher.A method to determine the emergency gas makeup flux range was proposed with comprehensive consideration of the cabin volume,the diameter of the leaking orifice,the lower limit of the total pressure and the oxygen partial pressure,and the time constraint to maintain the air pressure.The validity of the method was proved by two case studies.%针对载人航天器在密封舱体发生泄露时总压和氧分压的变化规律,建立了载人航天器舱压控制系统仿真模型,利用该模型分析了舱体容积、漏孔通径对总压和氧分压变化趋势的影响.结果表明,随着漏孔通径的增加或舱体容积的减小,总压和氧分压下降至指标下限所需的时间越来越短.随着漏孔通径的增加,舱体的初始漏气速率越高,但漏气速率下降得也越快.在分析的基础上提出了一种确定舱体应急补气速率取值范围的确定方法,综合考虑了舱体容积、漏孔通径、氧分压和总压下限要求、氧分压和总压维持时间需求,并通过两个算例验证了该方法的有效性.
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