Design of an Oxygen Turbopump for a Dual Expander Cycle Rocket Engine

The design of a pump intended for use with a dual expander cycle (LOX/H2) engine is presented. This arrangement offers a number of advantages over hydrogen expander cycles; among these are the elimination of gearboxes and inter-propellant purges and seals, an extended throttling range, and higher engine operating pressures and performance. The target engine has been designed to meet the needs of Phase III of the Integrated High Payoff Rocket Propulsion Technology (IHPRPT) program; thus, this pump must meet the program's reliability, maintainability, and service life goals. In addition, this pump will be driven by warm gaseous oxygen. In order to meet the needs of this engine, the pump will need to be capable of delivering 106 lbm/s (48.1 kg/s) at 4500 psi (31 MPa); this will necessitate a turbine capable of supplying at least 2215 hp (1652 kW). The pump and turbine were designed with the aid of an industry standard design program; the design methodology and justification for design choices are presented. Appropriate materials of construction and bearings for this pump are discussed.