Venting Simulation of Multiple Compartment Spacecraft

The transient pressure history experienced by spacecraft during launch and ascent creates pressure differences that have to be accounted for in the mechanical design of different spacecraft components. In addition, for high power applications, the venting times must be estimated to ensure that the pressure has dropped below the critical value for corona for both ground testing and in orbit power up. Therefore, an accurate design tool for simulating the venting of multiple enclosures was developed. The Spacecraft Venting Simulation Software (SVSS) calculates the mass flow rates, pressures and pressure differentials for multiple interconnected compartments. The venting can be calculated for circular or annular connections. The flow process can be either isothermal or adiabatic and can simulate various ambient pressure profiles. The mass flow rate is calculated for either a continuum or a molecular flow regime. Friction loss encountered for high aspect ratio orifices is also taken into account. The results of different simulations are in good agreement with published in-flight venting data.