Learning Forum

[Karthik Remella]

Hello Experts,

When can I say my nozzle is 'choked'?

Thank you.

[Keyur Kanade]

Hello,

Choked flow typically occurs in a compressible gas flow through a Venturi tube (CD nozzle). For a fixed upstream pressure, as the downstream pressure is reduced, the mass flow rate at the throat of the CD nozzle increases. However, upon reaching a limit, a further decrease in the downstream conditions does not increase the mas flow rate of the fluid at the throat. This condition is referred to as a choked flow. The mass flow rate is dependent only on the upstream conditions as well as the density of the gas and does not depend on the downstream conditions.

Thanks.