The Influence of Liquid Rocket Engine Inducer Compliance and Mass Flow Gain Factor on Cavitation Surge Frequencies Free

A primary driver in cryogenic pump transfer functions is the presence of cavitation and cavitation instabilities in the pump’s inducer. Fluid mode frequencies in a water test loop are measured and confirmed to be planar wave surge (cavitation surge) through analysis of an array of dynamic pressure transducers. In addition, steady computational fluid dynamics (CFD) simulations are conducted and used to estimate the cavitation compliance and mass flow gain factor at both room temperature and elevated temperature where thermal suppression effects are dominant. Excellent agreement is found between measured fluid mode frequencies and predictions using compliance estimated from steady CFD and the inlet feedline inertance.