turbopumps

A turbopump is a turbine-driven pump used to feed propellants into a rocket engine at high pressure. It relies on energy extracted from a power turbine, typically driven by combustion gases from a gas generator or preburner, to drive pump impellers that raise the propellant pressure sufficiently for engine operation.

A turbopump assembly typically comprises a turbine stage, a pump stage with impellers, a drive shaft, bearings, seals, and a surrounding casing. The turbine converts hot, high-velocity gases into mechanical energy, transmitted through the shaft to the pump impeller(s). The pump increases propellant pressure and delivers flow to the engine feed system, often via a diffuser to convert velocity into pressure.

Turbopumps come in axial and centrifugal (radial) configurations. Some engines use separate turbopumps for different propellants, while others employ a single, multi-stage pump. They are common with oxidizer and fuel combinations such as LOX/LH2 and LOX/RP-1, among others.

Operationally, turbopumps must start reliably and accelerate to operating speed before engine ignition. They must withstand cryogenic temperatures, high shaft power, and rotor dynamics. Key design considerations include efficiency, turbine-expander characteristics, seals, bearing life, and proper staging to achieve the required pressure ratio and flow.

Historically, turbopumps enabled the high propellant pressures essential for modern rocket engines. Notable examples include the propulsion systems of the RS-25 space shuttle main engine and other engines in the RD-107/108 and RD-170 families. Today, turbopumps remain a core component of many rocket engine cycles to improve performance and efficiency.