I've done some considerable work on this... I also had the idea of using an Automotive turbocharger mated to a high pressure, shaft driven, liquid pump.
I chose H202 as it is what I am currently working with in my engine designs. It was also much easier to design around than using LOX. My design involved using a modified Garrett t3 turbo charger (was donated). I modified the exhaust inlet to accept a catalyst pack and propellant feed. (basically welded a very small Mono-prop engine sans 1/2 the chamber and nozzle to the inlet.) The turbo was fed by a small pressurized tank of H202 and controlled by a simple ball valve. I never got around to the actual pump design, as the gas turbine had too many issues to move forward. A couple of issues I ran into during testing were: Turbochargers are not very efficient gas turbines! Turbochargers, while designed to operate under fairly extreme heat, are not designed to operate under any real pressure. The exhaust pressure of an engine is very low in comparison. Controlling impeller speed was impossible without mating it to something. In an automobile, the backpressure from the compressor will limit the rpm and prevent over-spin. This would not be an issue if it were mated to a pump of some sort. Turbochargers need a lot of fresh, cool oil! Most turbochargers are made of cast iron. One can imaging what happens when decomposing H202 flows across this surface over time. Now, with some serious engineering, most of these issues can be dealt with. One can take the basic design of a turbocharger and fabricate a gas generator that overcomes these issues. The turbine blade design itself should be looked at for efficiency. I personally am now looking at designing from scratch. The basic design is still the same concept... I still plan to use H202, as it is fairly easy to get a lot of gas out of a fairly small amount of liquid. I'll update if I make any progress. Sean Patrick Daly -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Andrew Case Sent: Tuesday, June 24, 2003 5:41 PM To: Henrik Schultz Cc: ERPS (E-mail) Subject: Re: [ERPS] Has anyone on this list ever built a small (working) turbo pump? As far as I know, no amateur has ever built a working turbopump. I think it's within reach of an amateur with access to a well equipped machine shop and decent engineering skills. This has come up a number of times on the aRocket list, and I think at least one person is trying to do it. The general consensus seems to be that the way to do it is to use an automotive turbocharger and a barske type impeller. There are amateur turbine engines based on automotive turbochargers that might serve as the basis of a turbopump. Check out some of the links at the bottom of this page <http://www.usrcjc.org/turbine_corner.htm> for some hobby turbine engines. One of the things that an amateur turbopump builder will need is a gas generator. This has a lot in common with a rocket engine igniter, which is one of the reasons I'm currently building one (igniter, not GG) in collaboration with some of the other folks on Arocket. Once we have a working design I think a gas generator should be relatively straightforward. Alternatively, if HTP is one of the propellants the GG is pretty simple. I just checked the aRocket archives and I see you've posted to the list, so no doubt some of this is old hat. Anyway, I think the place to start is with a proven gas turbine design and modify that into what will probably be a very poorly performing turbopump. Once you've learned a bit from the modified turbine you'll have a solid basis to build a higher performance turbopump. If you can build a turbopump you will have little difficulty in finding collaborators to work on engines, airframe, guidance, structure, etc. ......Andrew On Tuesday, June 24, 2003, at 05:11 PM, Henrik Schultz wrote: > Just got to wonder... lots of talk about how difficult it is to built > reliable and efficient turbo pumps... lots of good intentions to > experiment... > > But has anyone ever succeeded in building a small-scale pump suitable > for > amateur use, and who would be willing to share anything from a rough > sketch > to a detailed blue-print? > > Cheers - Henrik > > ---------------------------------------------------------------------- > Henrik Schultz Schultz Software > Senior Systems Architect IT Services and Solutions > http://www.schultz-software.dk/ Tel: +45 3963 4856 > > _______________________________________________ > ERPS-list mailing list > [EMAIL PROTECTED] > http://lists.erps.org/mailman/listinfo/erps-list > -- Dr. Andrew Case, PhD. Institute for Research in Electronics and Applied Physics, University of Maryland, College Park "It is seldom that liberty of any kind is lost all at once." - David Hume _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
