Газ турбинасымен жұмыс істейтін сорғы (Gaz turbinasy men júmys isteytin sorğı)

Pump driven by a gas turbine
the fuel pump

A turbopump is a propellant pump with two main components: a rotodynamic pump and a driving gas turbine, usually both mounted on the same shaft, or sometimes geared together. They were initially developed in Germany in the early 1940s. The purpose of a turbopump is to produce a high pressure fluid for feeding a combustion chamber or other use. While other use cases exist, they are most commonly found in liquid rocket engines. There are two common types of pumps used in turbopumps: a centrifugal pump, where the pumping is done by throwing fluid outward at high speed, or an axial flow pump, where alternating rotating and static blades progressively raise the pressure of a fluid. Axial flow pumps have small diameters but give relatively modest pressure increases. Although multiple compression stages are needed, axial flow pumps work well with low density fluids. Centrifugal pumps are far more powerful for high density fluids but require large diameters for low density fluids.

High pressure pumps for larger missiles had been discussed by rocket pioneers such as Hermann Oberth. In mid 1935 Wernher von Braun initiated a fuel pump project at the southwest German firm Klein, Schanzlin & Becker that was experienced in building large fire fighting pumps. The V 2 rocket design used hydrogen peroxide decomposed through a Walter steam generator to power the uncontrolled turbopump so V 2 turbopumps and combustion chamber were tested and matched to prevent the pump from overpressurizing the chamber.

The principal engineer for turbopump development at Aerojet was George Bosco. During the second half of 1947, Bosco and his group learned about the pump work of others and made preliminary design studies. Aerojet representatives visited Ohio State University where Florant was working on hydrogen pumps, and consulted Dietrich Singelmann, a German pump expert at Wright Field. Bosco subsequently used Singelmann's data in designing Aerojet's first hydrogen pump. By mid 1948, Aerojet had selected centrifugal pumps for both liquid hydrogen and liquid oxygen. They obtained some German radial vane pumps from the Navy and tested them during the second half of the year. The Electron Rocket's Rutherford became the first engine to use an electrically driven pump in flight in 2018.

Most turbopumps are centrifugal the fluid enters the pump near the axis and the rotor accelerates the fluid to high speed. The fluid then passes through a volute, which is a progressively enlarging pipe (in a spiral pattern); or a diffuser, which is a ring with multiple diverging channels. This causes an increase in dynamic pressure as fluid velocity is lost. The volute or diffuser turns the high kinetic energy into high pressures (hundreds of bars is not uncommon), and if the outlet backpressure is not too high, high flow rates can be achieved.

Axial turbopumps also exist. In this case the axle essentially has propellers attached to the shaft, and the fluid is forced by these parallel with the main axis of the pump. Generally, axial pumps tend to give much lower pressures than centrifugal pumps, and a few bars is not uncommon. Their advantage is a much higher volumetric flowrate. For this reason they are common for pumping liquid hydrogen in rocket engines, because of its much lower density than other propellants which usually use centrifugal pump designs. Axial pumps are also commonly used as "inducers" for centrifugal pumps, which raise the inlet pressure of the centrifugal pump enough to prevent excessive cavitation from occurring therein.

Steam turbine powered turbopumps are employed when there is a source of steam, e. g. the boilers of steam ships. Gas turbines are usually used when electricity or steam is not available and place or weight restrictions permit the use of more efficient sources of mechanical energy. One of such cases are rocket engines, which need to pump fuel and oxidizer into their combustion chamber. This is necessary for large liquid rockets, since forcing the fluids or gases to flow by simple pressurizing of the tanks is often not feasible; the high pressure needed for the required flow rates would need strong and thereby heavy tanks. Ramjet motors are also usually fitted with turbopumps, the turbine being driven either directly by external freestream ram air or internally by airflow diverted from combustor entry. In both cases the turbine exhaust stream is dumped overboard.