Try,

http://naca.larc.nasa.gov/reports/19...ca-tm-1212.pdf

& off you go. ■

hello, shenjie2004

the back pressure / inlet pressure of Laval nozzle is less than the critical pressure , so the air flow rate is constant, so it is a air flow control valve, from the formua( you can see from any kind fo fluid dynamic book) , when the air flow rate is constant, so it is only determined by the inlet pressure of Laval , so it is line proportion.

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Could somebody give a formula for calculating flow volume through a laval nozzle? ■

The volumtric flow rate, V (m3/s), for air flowing through a choked flow nozzle of throat diameter, d (m), with upstream pressure, p (N/m2 absolute) and upstream temperature, T (K), for air is given by:

V = 0.0259 x p x d2 / sq root T - - - m3/s of free air

The entire derivation from basics will be found in my Pneumatic Conveying Design Guide (in SI units) or in my Handbook of Pneumatic Conveying Engineering (in US engineering units). ■

Thanks David. Is is possible that you could send me the derivation about the formula you have given? ■

the research of the adjustable thorat area LAVAL nozzle is my Master thesis, from my test , i think the formula can be used for adjustable, but it need further research the influence of turblent layer on the flow,.

best regards

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