航天器电推进系统氙气工质充装特性模型与评估

Modeling and Evaluation of Xenon Charging Characteristics for Spacecraft Electric Propulsion

氙气充装特性计算与评估是航天器电推进系统应用的关键因素之一,通过试验及应用国内外试验数据库,建立了氙气工质全区域修正性的经典热力学状态方程、经验方程及多参数方程,比较分析了三种不同计算模型在单相区、临界区及超临界区与试验数据的偏差,新建立Helmholtz方程计算的压力密度,与试验数据比较,该模型比NIST方程有更高的精度,通过比较分析验证了计算模型的正确性与高精度,完全能满足电推进系统氙气工质充装特性数值模拟与预估的要求。

The fluid-state behavior and charging characteristics of realistic xenon, an advanced gas medium in spacecraft electric propulsion , were mathematically modeled, theoretically analyzed, experimentally evaluated either with the lab-built platform or by searching the measured results reported in literature or in accessible databases. First, the modified classical thermodynamics, empirical and multi-parameter equations were derived;next, the xenon pressure/density in single-phase, critical and supercritical states, experimentally measured and analytically calculated by solving the newly-derived equations, were compared for deviation estimation;and finally, new Helmholtz equation was developed to more precisely calculate xenon pressure/density in gas, liquid and supercritical states. The check-up results show that the newly-developed Helmholtz equation outperforms NIST equation because of higher precision. For example, the relative discrepancy between the measured and calculated results was found to be below 0.5%(about 0.05%) in 273 -358 K (358 .373 K) range.