Sizing an emergency venting system for a cryogenic dewarIf the vacuum vessel that insulates a cryogenic dewar for a spaceborne experiment prior to launch is damaged, air will leak into the vacuum insulation space. As the sudden heat load causes the pressure to rise in the dewar, a safety disk in the emergency vent line will burst at the design pressure differential to allow vaporized cryogenic fluid to escape. The emergency vent line should be sized such that sufficient gaseous cryogen will be vented to keep the pressure inside the dewar below the design limit. On the other hand, the line should not be so large as to impose an unnecessary heat load on the dewar filled with cryogenic fluid. A vent-line computer program was generated to compute the maximum flow rate allowed for a proposed vent-line system. Parametric studies have been carried out for different burst disk pressure differentials, liquid cryogen ullage, and vent-line sizes.
Document ID
19870063500
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Liu, C. K. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Naes, L. G. (Lockheed Missiles and Space Co. Palo Alto, CA, United States)
Manikowski, A. F., Jr. (Lockheed Missiles and Space Co., Inc. Research and Development Div., Palo Alto, CA, United States)