Turbo pump ASCII art
In a comment to a post by John Hare (Told You So - Seleneian Boondocks), I tried to post an ASCII art depiction of a turbo-pump configuration which I thought would better illuminate the point I was trying to make. Unfortunately, the reply window only allows a subset of the HTML markup and decided to severely mangle my ASCII art instead. It really was a good rendering, so I'll post it here, just in case anyone else is curious.
|| __ _____ __ ||
||^|__| V |_____| V |__|^||
|| < :=======| |=======: > ||
||____| V _|^|_ V |____||
|_____| |_| |_| |_____|
V |^| V
What you are looking at is the bottom of a proposed thrust chamber analog. High pressure gas is being fed into the chamber and forced down and out ("V" in the diagram) through a turbine blade. The blades are hollow, which allow them to act as a pump (through centrifugal acceleration). Water is then pumped into the chamber through a diffuser along the paths marked by ("<", ">", and "^").
As I mentioned in the comments to the other post, the key to making this design work is minimizing the amount of drive gas which gets leaked into the pump chamber around the ends of the turbine blades. Just as the water within the blades is going to want to be thrown outward, so will the gasses escaping through the blades themselves.
Anyway, before I reveal just how much I don't know about turbopump design, I better just quit now. Feel free to comment on this here or at the original post.