On Sat, 2004-06-12 at 18:32, Stump wrote: > roger gregory <roger <at> halfwaytoanywhere.com> writes: > > > > > The thrust is just sufficient to pump the propellant to the exhaust > > velocity. So that's not the answer. However the energy imparted to the > > fuel is same as in the exhaust (the same v after all) and thus the > > temperature of the reaction is pushed higher and the fuel is more > > disassociated. The higher energy and temperature raise the exhaust > > velocity until this converges. The energy is thus in the disassociated > > combustion products and heat. > > > > Not entirely true. I am assuming that "energy imparted to the fuel" refers to > the heat released from the reaction in the combustion/catalyst chamber. Some of
There's where you are wrong. Lets step back a bit. What we are talking about is. >Consider a rocket, say 200 seconds; mounted on an arm pivoting >on a central spindle. The propellant enters the rocket along a tube up >the central spindle, goes through a frictionless coupling and then >follows the tube along to the rocket tip. The energy imparted to the fuel by the pumping process is 1/2 m v^2 where both the m and the v are the same as the exhaust velocity, by design of the experiment. Then we add the chemical energy, and get a higher temperature than we would have otherwise had. This causes higher disassociation. We are way far away from the Carnot limits here, the exhausts of almost any rocket are quite hot. The rest of what you say is of course true but not to the point of this particular gedanken experiment. Roger Gregory [EMAIL PROTECTED] http://www.halfwaytoanywhere.com _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
