Gas Volume Evacuation Characteristics for Closed Volumes and the Thermal/Fluid Effect of Discharge Process on Attached Hardware for International Space Station Environmental Conditions

The Vacuum Access System (VAS) is used for ISS experiment chamber evacuations and to remove air from furnace experiment sleeves. The evacuation process thermodynamically reduces the temperature of the gas being evacuated which then cools the temperature of attached hardware. This cooling effect can present problems to the environment if it reaches the local ambient dewpoint temperature. This paper presents real and ideal gas thermodynamic relationships as an application to determine the discharge characteristics of the VAS evacuation process and determine the heat transfer rate to the surrounding and attached hardware.