Interaction of the Gas-vapor Mixture and Air on the Condition Drainage System of Space Launch Vehicles When Filling Cryogenic Propellant

The process of interaction between the chilled drain pipe oxidizer tank with atmospheric air. The conditions when drain- pipes, depending on ambient parameters (temperature, relative humidity). Using modeling package SolidWorks Flow Simulation software processes carried out: a) the expiration of the steam-gas mixture through the drainage and pressure relief valve and drain pipe; b) contacting with chilled air drainage pipe. It is shown that a) during the expiration of the gas mixture the drain pipe cools; b) when closing the safety valve, drainage atmospheric air enters into the drainage pipe, and water vapor condenses and freezes, which can lead to the blockage of the drainage pipe and the explosion of the propellant tank. Recommendations to prevent freezing of the drain pipe.