Thermodynamic vent system performance testing with subcooled liquid methane and gaseous helium pressurant

摘要

LCH_4 testing was conducted at the Marshall Space Flight Center using the multipurpose hydrogen test bed (MHTB) to evaluate the performance of a spray-bar thermodynamic vent system (TVS) with sub-cooled LCH_4 and gaseous helium (GHe) pressurant. Thirteen days of testing were performed in November 2006, with total tank heat leak conditions of about 715 W and 420 W at a fill level of approximately 90 percent. A total of 23 TVS cycles were completed. The TVS successfully controlled the ullage pressure within a prescribed control band but did not maintain a stable liquid saturation pressure. This was likely due to a TVS design not optimized for this particular propellant and test conditions, and possibly due to a large artificially induced heat input directly into the liquid.