In a convergent nozzle, the ducting narrows progressively to a throat.
2.
Convergent nozzles are used on many jet engines.
3.
C-D nozzles can accelerate the jet to supersonic velocities within the divergent section, whereas a convergent nozzle cannot accelerate the jet beyond sonic speed.
4.
If the nozzle pressure ratio is above the critical value ( about 1.8 : 1 ) a convergent nozzle will choke, resulting in some of the expansion to atmospheric pressure taking place downstream of the throat ( i . e . smallest flow area ), in the jet wake.
5.
When the pressure ratio across a convergent nozzle exceeds a critical value, the flow " fixed " convergent-divergent nozzle used on a conventional rocket motor, those on turbojet engines must have heavy and expensive variable geometry to cope with the great variation in nozzle pressure ratio that occurs with speeds from subsonic to over Mn3.
मोबाइल