Today, rockets are used to transport satellites and humans into space. These rockets use a cluster of liquid-propellant engines to generate thrust in the lower stage – in some heavy-duty designs with solid-fuel boosters – and in the upper stage often a single liquid-propellant engine of the same type with a thrust nozzle adapted to the vacuum.
The enormous thrust generated by a liquid rocket engine is created by the combustion of high mass flows of fuel and oxidizer in the combustion chamber and the subsequent expansion of the combustion gases in the thrust nozzle.
Typically, each liquid-propellant engine has its own turbopump with two centrifugal pumps for fuel and oxidizer arranged on a common shaft. The centrifugal pumps are driven by an axial gas turbine, which is also mounted on this shaft and is supplied with combustion gases.
