Centrifugal Pump operating in zero gravity

[Ralph Varckette]

A colleague asked me a pump question that I was unsure of. He asked if a centrifugal pump was operating in a normal 1g application and produced 50 ft. of head (water at 21.7 psi for example), and then went into a 0g condition.
If - Pressure = (Weight Density) x (Head) = (Mass Density x g) x (Head)
Then – once gravity (g) nears zero, then Pressure will also go to near zero.

Is this correct?

 

[Compositepro]

No. The pump will develop the same head (pressure). Just as in a gravity field the outlet pressure of a pump is determined by the restriction to flow out of the pump. This restriction can be due to the rise in elevation of a pipe in gravity, or to a valve, or to pipe friction.

There might be some issues of getting water into the pump. Air pressure will still push without gravity but liquid will not go to the bottom of a feed tank without gravity or some piston. Before main engines are fired on a rocket in space small jets are fired to slightly accelerate the rocket so fuel and oxidizer moves to the bottom of the tanks.

 

[Ralph Varckette]

Thanks! – That was the first time I was asked about a pump application with a gravity condition.