气体间漏率等效关系的直接模拟蒙特卡洛分析

Equivalence Relation of Leakage-Rate Measured with Different Tracer Gases:A Study in Direct Simulation Monte Carlo Method

研究气体间漏率的等效关系,对提高检漏数据判读的准确性具有重要意义。本文基于对金属压扁型漏孔的研究,通过建立分析模型,运用直接模拟蒙特卡罗法数值模拟方法得出了气态工质的漏率曲线及不同工质间漏率的等效关系,验证了气态工质泄漏模型的正确性,可实现已知示漏气体漏率情况下实际工质漏率的虚拟预示。研究结果表明,不同气态工质在同一条件下漏率存在着较大差异,但都随两端压差增大而增大,呈近二次多项式变化趋势,仿真结果与理论分析相符。气态工质间漏率等效性在He漏率≤10-6Pa·m^3/s和He漏率≥10-3Pa·m^3/s时趋于恒值;而当He漏率在[10-6,10-3]Pa·m3/s时,漏率等效性存在着先上升后下降的多项式变化形式,且最大值出现在这一区域之间。研究结果为实际工质与示漏工质间漏率等效数值研究提供了基本方法和参考数据。

The leakage-rate,measured with the tracer gases including He,Kr,Ne,N_2 and CF_4 through a leak of narrow rectangular metal-slit,was mathematically modeled,theoretically analyzed and numerically calculated in direct simulation Monte Carlo（ DSMC） method. The influence of the pressure-difference and tracer-gas type on the leakage-rate correlation was investigated. The results show that depending on the pressure,the leakage-rate of the tracer gases other than He can be transformed into that of He. For example,though quite different,the leakagerates of all tracer gases quadratically increase with an increase of pressure. In He leakage-rate ranges,below 10-7 or above 10-3 Pa · m^3/s,the leakage-rate equivalence relation remains almost unchanged,whereas in 10-7~10-3 Pa·m3/srange,it polynomially changes in an increase-decrease mode,peaking somewhere in between. We suggest that the newly-developed leakage-rate equivalence relation be of some technological interest in leak detection.