称重法低温介质流量校验系统方案研究

液体火箭发动机试验中，流量测量的准确度至关重要。不同于常温流量测量，低温推进剂的流量测量有其特殊性。介绍了称重法低温介质流量校验原理、方法及方案，对流入法排出气体及流出法增压气体流量简略计算公式进行了推导；针对低温容器气枕换热传质特点，对气枕平均温度的一致性进行了讨论。得出了流入法排出气体流量一致性较好、采用流入法可以使低温流量计检定准确度更高的结论。

Scheme Research on Cryogenic Flow Weighting Calibration System

It is critical for the measurement accuracy of flow rate in the liquid rocket engine test. Different from the flow rate measurement at normal temperature, there are many special characters in flow rate measurement for cryogenic propellant. The principle and scheme of the calibration for cryogenic flow rate in weighting method are introduced. The formulas of ullage flow rate in inflow and outflow conditions are deducted. In the discussion of thermal stratification of ullage, the heat and mass transfer mechanisms in cryogenic tank are considered. In the end, it draws a conclusion that inflow weighting method leads to higher accuracy to calibrate the cryogenic flow meter, because of the better stability of ullage flow rate in the inflow method.