Space
Rocket turbopumps
The most powerful pumps for their size ever built — and the reason big rockets can fly at all.
- Saturn V F-1 engine
- turbopump of about 55,000 horsepower
- F-1 pump speed
- about 5,500 RPM
- Space Shuttle fuel pump
- about 35,000 RPM
- Job
- feed fuel and oxygen at very high pressure
Numbers are rounded, typical values — real machines vary.
Why rockets need pumps
A big liquid-fuel rocket burns tonnes of propellant every second, and the combustion chamber is at very high pressure. To get the fuel in, it must be pushed in at even higher pressure.
Squeezing the whole fuel tank to that pressure would need tank walls far too heavy to fly. So the tanks stay light, and a does the pushing.
A turbine driving an impeller
A small amount of propellant is burned to make hot gas, which spins a . On the same shaft sit one or more — often — that raise the pressure of the fuel and the liquid oxygen.
Because the tank pressure is low, the inlet is right on the edge of . Many turbopumps add an inducer — a screw-like axial stage in front of the impeller — just to raise the pressure a little before the main vanes.
Physics you already know
Enormous head from a small wheel means high (Euler: H = u₂·cᵤ₂/g). Keeping above required is the hardest part of the design.