A Study on the Balance Piston Design of Turbopump Considering Dynamic Characteristics

Abstract

Rocket engine tubopumps adopt balance piston (BP) in order to balance large axial thrust generated from high discharged pressure of the pump. BP is a self-thrust balancing system and quasi-statically stable, but might become unstable due to compressibility of liquid hydrogen, one of the major propellants of rocket. Conventional BP design methods mainly focused on the static characteristics such as thrust balancing ability and volumetric loss. However, a dynamic characteristic, that is stability of axial direction, is not well considered. In this paper the relationship between static and dynamic characteristics are investigated by numerical and theoretical study, and it is concluded that static and dynamic characteristics should be considered simultaneously in BP design.