Optimal Design of Rocket Turbopump Self-Balance System for Rocket Pump considering operating environment

Abstract

Rocket turbopump has low-pressure section and high-pressure section within a single system. The pressure distribution generates large axial thrust against the rotor. The rocket turbopump balance piston (BP) has the function to autonomously adjust this axial thrust. The operating mechanism of BP is as follows: (1) the rotor moves axial direction when the axial thrust changes, (2) the cross-sectional area of the orifice at impeller back shroud changes, (3) the pressure loss at the orifice changes, (4) The axial thrust is adjusted. Functional verification of the BP is performed by a turbopump test. Therefore, when design changes are implemented, it is necessary to return the upstream design stage. Rocket turbopump, which require high reliability, must be designed to restrain such return risk. In this study, 1DCAE, which performs functional design in the upstream design stage, and robust design, which reduces the effects of variation that occurs in the operational stage, were used. Robust optimization of BP was performed to find the optimal conditions that can restrain axial motion better than the current situation.