发动机试验液氢流量测量不确定度评定

Uncertainty evaluation of liquid hydrogen flow measurement in rocket engine test

针对某型号液体火箭发动机试验,介绍了液氢低温流量测量系统组成及原理。根据液氢质量流量测量数学模型,分析影响液氢流量测量不确定度的主要压力对贮箱容积的影响因素,依据不确定度评定相关标准和方法,对各种影响因素进行分析,最终得出液氢质量流量扩展不确定度为±0.88%,满足发动机设计部门对液氢低温质量流量测量不确定度±1%的要求。

The composition and principle of the liquid hydrogen flow measurement system used in the test of a liquid rocket engine are introduced in this paper. According to the mathematical model of liquid hydrogen mass flow measurement, the influence of main pressure on storage tank volume is analyzed, which is the main factor to affect the uncertainty of the liquid hydrogen flow measurement. The various factors of affecting the uncertainty is analyzed according to the uncertainty evaluation＇ standards and methods. It is concluded that the expanded uncertainty of liquid hydrogen mass flow is ±0.88%, which can meet the ＋ 1% uncertainty requirement made by the engine design sector for the liquid hydrogen low-temperature mass flow.