This is a test run to check the relationship between rotor speed, pressure, and temperature with one NGV blocked off AND using a fully bladed (unclipped) turbine exducer. The results here are a little disappointing given that at 120KRPM she is only producing ~20psi of pressure and at maximum TOT (850C). I pushed her a little overspeed to see the result and you can see the P2 of 22psi at ~128KRPM and definitely overtemping at 900C. They will run like this for a brief time without coming apart but sustaining at this temperature will end up destroying the turbine and/or overtemping the rear bearings. As the P2 pressure rises it will compress the combustion of fuel more densely to prevent the combustion cycle from wicking into the NGV and turbine. Additionally, as the engine is tuned to operate within the compressors optimum efficiency, it requires less energy from the turbine to drive the compression stage. This will result in lower temperatures required through the turbine to drive the comp stage and will improve the engines thrust capacity. It will also improve the startup process notably as well - with the system running low P2 relative to massflow, it makes the spoolup a bit tricky and you have to be patient in getting her up to speed without big flames blowing through the turbine wheel. The next step is to block off an additional NGV runner and retesting to see what the P2 pressure comes up to at ~120K. The compressor will operate at maximum efficiency with an RPM of 115K and a P2 of 26psi so the idea here is to trial and error the NGV flow area until the engine achieves this operating condition. At this point the engines mechanical layout is optimally refined and then measurements can be taken within the jetpipe to get an idea of what kind of total power is available to drive a freepower turbine section for shaft power.
Posted on: Tue, 14 Oct 2014 00:32:50 +0000
Trending Topics
Recently Viewed Topics
© 2015