An extensive thermal testing program was performed in an arc tunnel facility in support of an IUS second stage solid rocket motor (SRM) requalification activitiy. A three-phase laboratory thermal study of failure scenarios resulted in the following items. First, bursting of the SRM environmental closure was pressure rather that temperature dependent, which allowed full scale cold gas simulation of the closure burst sequence. Secondly, arc tunnel ablation measurements of EPDM, a thermal insulative rubber material covering the SRM ignitor housing, were made in both convective and radiative heater environments under varied sample vibration levels to simulat the measured motor vibration environment. The EPDM radiation recession rate scaled to the SRM environment (6000R, 600 psia peak chamber conditions) was about 3.7 mil sec-1 in agreement with later static test firing measurements, indicating the motor case heat transfer environment near the ignitor housing to be basically and remarkably purely radiative and virtually uninfluenced by char loss due to vibration or convection. Thus EPDM showed itself to be a very effective SRM thermal protection material. Finally, hot gas leakage past a grafoil seal emerged as the most likely SRM failure scenario. Arc tunnel testing of silica phenolic thermal insulation candidates to protect the SRN nozzle titanium 'techroll' housing resulted in verification of a satisfactory design concept which has since been implemented in successful flight hardware.
Inertial upper stage thermal test program
Thermisches Testprogramm fuer die obere Stufe unter Schwerkraft
AIAA-Papers ; Jun ; 1-9
1987
9 Seiten, 8 Bilder, 6 Tabellen, 7 Quellen
Conference paper
English
Inertial upper stage thermal test program
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