齿轮泵在航天两相回路中的使役特性研究

Research on Ordered Characteristic of Gear Pump in Two-phase Loop of Spacecraft

为提高航天用液氨类齿轮泵的使役性能及在机械泵驱动两相回路(MPTL)中的匹配性能,研究了基于该两相回路的用泵特点并精确计算了泵的容积效率,由泵输出流量、容积效率的输出特性得出泵转速的使役特性并进行实例运算及灵敏度分析。结果表明:液氨类介质泵的容积效率一般比较低;泵的输出流量具有与转速的正线性、压差的负线性、介质黏度的负反相关的比例特性;泵的容积效率具有与压差/转速的负线性相关特性,适宜于高速、轻载工况;泵的使役转速具有与MPTL回路流量的正线性、回路压差的负线性、回路介质黏度的负反相关的比例特性,宜用于压差/转速(流量)恒定的回路工况;案例的介质黏度小于0.00419 Pa s的区域为压差敏感的低黏度区,否则为流量敏感黏度区。所得结论为液氨类航天用泵的进一步研究与开发,提供了理论依据。

To improve the ordered characteristic of external gear pump with liquid ammonia medium for the purpose of better matching dynamic performance of mechanically pumped two-phase loop(MPTL)in large spacecraft,based on the pump's required characteristic by MPTL and the precise calculation of volume efficiency are researched.From the output characteristic such as flux and volume efficiency,the ordered characteristic of revolving speed was derived;finally,the related sample calculation and sensitivity analysis were carried on.All results show that volume efficiency of the gear pump with liquid ammonia medium is generally low;the output flux is positive linearity with revolving speed and negative linearity with pressure difference,and negative inverse linearity with viscosity of working medium.The volume efficiency is negative linearity with the ratio of pressure difference to revolving speed,so it is suitable for high speed and light load condition;the ordered revolving speed is positive linearity with required flux of MPTL and negative linearity of required pressure difference of MPTL and negative inverse linearity with viscosity of working medium,so it is suitable for the approximately fixed ratio condition of pressure difference to revolving speed;the ordered revolving speed is more sensitive to required pressure difference than required flux when medium viscosity is less than 0.00419 Pa s,otherwise,the ordered revolving speed is more sensitive to required flux than required pressure difference.So a previous theoretical basis is provided for further research and development for the external gear pump with liquid ammonia medium used by MPTL of spacecraft.