Hello everybody!

I am a student designing a liquid methane centrifugal pump for my final school project and i require some help from people with more experience in this domain as pumps are not exactly my domain of activity!
So, i already designed the liquid methane pump and for testing purposes i designed a water pump prototype using the pump affinity laws. My problem lies with actually testing the water prototype pump. As the methane pump is designed for a rocket engine, it will take methane with a pressure of 3 bars from the methane tank so, in order to properly test the water pump, it will also need to have water at 3 bars at the inlet. This would also improve cavitation performance as it is very unlikely that water at 3 bars will drop under the vapor pressure. The thing is, the water pump has a very small flow rate, 0.8 kg/s to be exact, so it requires an intake pipe with quite a small diameter, around 1/4", for a tank pressure of 3 bars.

I have not been able to find a way of providing water at a pressure of 3 bars while also maintaining that design flow rate, because the water pressure would instantly drop as it enters the 1/4" diameter pipe from the pressurised tank, not even taking into account the hydraulic pressure losses due to water friction in such a small pipe...

I tought of simply using a tank with water at such a high pressure that even after the pressure drop in the 1/4" pipes, it would still have at least 3 bars at the pump inlet, but then, due to higher pressure difference between tank and pump, water will achieve higher speed in the pipe and therefore the design flow rate will not be achieved.

I would like to ask if anyone has any idea what alternatives i have, if there are any?