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

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.