节流参数对液氮贮箱热力排气系统运行特性的影响

Effect of throttle parameters on operating performance of thermodynamic vent system in liquid nitrogen tank

为了研究低温推进剂贮箱的控压特性和热力排气系统的运行特性,搭建了一套以液氮为贮存工质的低温流体高效贮存平台,用于模拟液氧贮箱在热力排气系统运行下的压力变化规律。采用单一变量控制法,进行了不同节流比和节流形式下的液氮贮箱热力排气系统控压的实验研究。分析了不同节流参数下液氮贮箱的压力、温度变化特性和排气质量损失。研究发现,当节流比从2%增大到16%时,系统运行占空比从3.42减小到了2.31,但流体损失量也从0.5%增加到了3.3%。以减少系统工作时间和流体质量损失为原则,得到了液相节流条件下热力排气系统的最优节流比为8%。节流开度同样对热力排气系统的制冷量影响明显,小开度带来的大压差有利于提高系统制冷量。

In order to investigate the pressure control behavior of cryogenic propellant tank and operating performance of thermodynamic vent system (TVS), a set of high-efficiency cryogenic fluid storage platform with liquid nitrogen as storage medium was set up, to simulate the pressure variations of liquid oxygen tank under the operation of TVS. The single variable control method was used to carry out the experimental research, which concentrate on the pressure control of TVS in a liquid nitrogen (LN2) tank with different throttle rates and modes. The pressure, temperature variations and vent mass loss of LN2 tank under different throttling parameters were analyzed. It was found that the duty rate of TVS decreases significantly with the increase of throttle rate, and the cooling capacity of the system is increased, which greatly reduces the TVS operating time. Based on the principle of reducing the working time and fluid mass loss, the optimal throttling ratio of TVS is obtained. On the other hand, the throttle opening has a remarkable influence on the cooling power of TVS, the large pressure difference helps to improve the cooling power.