PROPELLANT FROST EFFECT ON OPERATION OF THE TRANSTAGE BIPROPELLANT PILOT VALVE UNDER THE LOW PRESSURE ENVIRONMENT.
Final rept. Dec 65-Feb 66,
AIR FORCE ROCKET PROPULSION LAB EDWARDS AFB CA
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This effort was an attempt to duplicate, if possible, the suspected flight failure mode of propellant frosting of the Transtage Engine bipropellant valve on the Titan III-4C vehicle. This propellant frosting was due to the venting of propellant leakage through the bipropellant pilot valve vent tube into the hard vacuum of space. Tests were conducted at altitudes between 400,000 and 825,000 feet. A Transtage bipropellant valve was tested under both normal and abnormal conditions, i.e., induced internal valve leakage 50 UDMH-50 N2H4 ranging from 4 ccmin to 200 ccmin. Other tests included impingement of fuel leakage on the bipropellant valve as well as on adjacent engine components. The analysis of the test results revealed that internal valve leakage, at environmental temperatures of about 35 F, can result in erratic valve operation and in some cases can cause valve malfunction due to frost blockage of the bipropellant pilot valve vent tube. The impingement of fuel leakage on the bipropellant valve, from a distance of 3 inches, can cause blockage of the valve mechanical linkage as a result of propellant frost accumulation. Author
- Rocket Propellants