serre@boulder.Colorado.EDU (SERRE GLENN) (11/20/90)
In article <1990Nov16.211340.27611@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >A badly overexpanded nozzle causes the gas flow to break away from the >nozzle wall before reaching the end, which causes all manner of nasty >turbulence and problems of various kinds. The SSME nozzles are in fact There is, however, one good effect from separation in an overexpanded nozzle: If the flow didn't separate (which it usually does at ~0.4 times ambient) then the exit pressure would be even lowe, resulting in a greater loss of thrust (compared to the separated case). >>to adapting the RL-10 to operate at sea level. Is this a good example of >In principle, all you need is a shorter nozzle, although you have to think >about things like the effect on the cooling system. There may be some >issues in ignition, too. Since the RL-10 "bootstraps" on ignition (uses energy from tank pressurization to spin-up the turbines), you'd have to pressurize the fuel and ox tanks to about 20 lbs/in2 over atmospheric (for the Centaur G-prime RL-10s). I can't imagine that this would be a problem, though. Trivia and ramblings from --Glenn Serre gaserre@nyx.cs.du.edu (serre@tramp.colorado.edu will disappear soon. :-( )