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

The leakage-rate, measured with the tracer gases including He, Kr, Ne, N₂ and CF₄ 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 · m³/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.