Inlet Cover Treatment to Enhance Zero NPSH Inducer Operation

Zero net positive suction head (NPSH)-capable hydrogen pump inducers are a critical component needed to lower the cost and increase the effectiveness of Nuclear Thermal Propulsion (NTP) engines. Zero NPSH pumps need to be able to pump up to 55% vapor fraction by volume without significant head fall-off. Current technology inducers can pump liquid hydrogen up to a limit of about 25% vapor fraction by volume because of choking of the vapor in either the inlet pipe or the inducer blade passage. It is proposed that the Concepts NREC (CN) inlet cover treatment cavitation and stability control device (SCD) will be able to increase the hydrogen vapor volume pumping fraction to the required 55%. The device allows the inducer to operate stably at high blade angles and low flow coefficients which increases the blade passage and the inlet pipe area to delay choking of the pumped fluid.