hi all, i have a graduation project in university, which is carbon-carbon based rocket nozzle design.
I have a question about bell-shaped nozzles.
Well, on books it writes that, "bell-shaped nozzles are efficient on an optimum altitude". Well according to formula,
F=m.̇v2+(p2-p3 ).A2
if the atmospheric pressure is lower than the nozzle exit pressure, performance increases. Thrust increases, specific impusle increases. So where is my error ? How can "bell-shaped nozzle is efficient on an optimum altitude" be possible?
I have a question about bell-shaped nozzles.
Well, on books it writes that, "bell-shaped nozzles are efficient on an optimum altitude". Well according to formula,
F=m.̇v2+(p2-p3 ).A2
if the atmospheric pressure is lower than the nozzle exit pressure, performance increases. Thrust increases, specific impusle increases. So where is my error ? How can "bell-shaped nozzle is efficient on an optimum altitude" be possible?