Alternate pump/compressor designs for turbopumps

[EVA_Reentry]

So. KSP has got me interested in designing (not making, but designing) liquid rocket engines. From my research, it seems that turbopumps have been limited to two types of pumps: axial, or centrifugal. However, there are other types of pumps for which I can't see any issues with besides RPM (and that can be solved with clever drive-shaft modifications). These are:

1. A staged Roots compressor- which has the advantage of creating a high amount of pressure while reducing risk of sloshing

2. A scroll compressor- which is compact, lightweight, and relatively efficient, making it a good candidate for upper stage and transfer engines

Any ideas you have, I would love to hear. What do you think?

[passinglurker]

What about xcor and their piston driven pump design?

[kunok]

You already said, both alternative types you suggested will need a drive shaft, so they are already more complicated. The scroll compressor as far I know is that a compressor not a pump.

Turbopumps are terribly simple and efficient.