Dynamic Amplification of Fluid Pressure in a Propellant Feed Line

Abstract

During the solid rocket booster phase (stage 0) of the Titan IV Space Launch Vehicle K-9  ight, an anomaly occurred in which a burst diaphragm in the stage I oxidizer tank pressurization system ruptured prematurely, resulting in abnormal stage I engine starting conditions. An investigation was conducted and it was found that the most probable cause of the anomaly was oscillatory ampliŽ cation of the  uid pressure in the pressurization system oxidizer supply line against a volume of trapped gas on the upstream side of the burst diaphragm. This system was driven by liftoff acceleration that induced oscillations in the main oxidizer supply system pressure. A model was formulated to calculate the oscillatory  uid pressure at the burst diaphragm and an experiment was devised to generate data for checking the validity of the model. The experimental setup included a  ight-conŽ guration pressurization system oxidizer supply line and a  uid system for inducing pressure oscillations in the liquid column in the line. The pressure of the trapped gas at the burst diaphragm was measured to determine the response to oscillatory  uid pressure imposed at the opposite end of the line. Agreement between the model prediction and experimental results is excellent.