摘要
对以液氮为工质的热力学排气系统进行了周期性压力循环控制实验,对实验循环过程中的气枕压力波动进行了测量,并对液相同步瞬时温度进行了实时监测。结果显示在前期混合模式阶段,由于外部环境漏热及内部低温泵功热持续向低温液体耗散与积累效应,液氮的平均温度上升速率为0.166K/h;而在后期并行运行模式阶段,低温液体通过节流膨胀产生了制冷效应,由于冷量的输入能够有效降低引起液相温升的热量,因而有效减缓了液体温度上升速率,有节流冷量输入的液体温升速率降低为0.0235K/h。通过数学模型对液相随气枕压力的温升变化速率及各运行模式终了温度进行了仿真,通过比较,发现计算结果与测试数据吻合较好。
The pressure control experiment was carried out on the cryogenic tank with thermodynamics venting system （TVS） using liquid nitrogen as the working medium, the ullage pressure fluctuation was measured during the cycles, and the synchronous temperature was monitored as well as the transient exhausting flow rate. The results show that in the mixing running stage, the average temperature rising rate of liquid nitrogen is about 0. 166K/h, which is mainly caused by heat leaks from sur- roundings and the cryogenic pump to the liquid; In the parallel running stage, because the cooling power produced by Joule - Thomson effect is transferred into the liquid, the available heat leading to the temperature rising of the nitrogen drop to a low level relatively, as a result the average temperature rising rate of liquid nitrogen decreases to 0. 0235K/h obviously. The temperature rising rate of liquid with ullage pressure and final temperature of each running mode were simulated through mathematical model, the comparison shows that the model agrees with test data well.
出处
《低温与超导》
CAS
北大核心
2018年第2期10-14,共5页
Cryogenics and Superconductivity
关键词
温升速率
节流制冷
热力学排气系统
压力控制
Temperature rising rate, Throttle refrigeration, TVS, Pressure control
