Converging Nozzle Ideal Ratios

[tripsahoy]

Hi everyone,

I am new to the topics of compressible flow, and this question has been racking my brain for a while. Is there an ideal area ratio for a converging nozzle at which it no longer is beneficial to shrink the exit hole due to increased vortex growth and/or heat? This is all assuming speeds of around 0.4 mach. Thanks!

 

[GregLocock]

Yes there is. If you reduce the outlet area too much you'll get Mach choking.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[btrueblood]

Unless your goal is to reduce the mass flow rate, in which case you can continue to reduce the hole as far as you want. You could even mount a needle on a screw thread and vary it in real time, oh wait, that's called a needle valve.

 

[mohr]

Hi Tripsahoi :

A0/A1 may be 1.2 / 1.3 (with gamma 1.4) and watching the back pressure to avoid Mach chocking as GregLocock said.
Cheers