氦质谱非真空积累检漏法待测时间研究

Waiting Time for Non-Vacuum Accumulation Leak Detection by Helium Mass Spectrometer: A Simulation Study

以Fluent的CFD仿真为手段,通过考查放样气体在某收集室内强迫对流的分布规律,来优化氦质谱非真空累积检漏法的待测时间。研究结果表明:该收集室在自带风机的作用下230 s内即达到了氦气的空间浓度分布小于3%的要求;建议该收集室的待测时间调整为5 min。本文的结论可以为氦质谱非真空累积检漏法的具体实施提供一定的技术支撑。

We addressed the waiting time required for the injected standard gas to be mixed uniformly with the leaked helium by forced convection and by diffusion in the accumulation chamber in non-vacuum accumulation leak detection of spacecraft by helium mass spectrometer. The flow field in the lab-built accumulation chamber was mathematically modeled,theoretically analyzed and numerically simulated with CFD software to optimize the waiting time. The simulated results show that the helium concentration distribution in the accumulation chamber can be less than 3% after 230 s under the forced convection condition,and that the optimized waiting time should be about 5 min. We suggest that the simulated results may be of some technological interest in non-vacuum accumulation leak detection of spacecraft.