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 wanghong April 4, 2005 20:29

what's relationship between flow rate and speed

Hi everybody.

i am simulating a species problem.i know when gas flow rate of the nozzle is a constant,a small diameter will make gas flow faster,but what's relationship between the speed and diameter and nozzle's flow rate?

Thanks for all!!

 pUl| April 4, 2005 23:11

Re: what's relationship between flow rate and spee

Equation of continuity?

v1 * rho1 * A1 = v2 * rho2 * A2

Where:

v = velocity/speed (m/s)

rho = density (Kg/m^3)

A = cross sectional area (m^2)

Assuming rho is constant:

v1 * A1 = v2 * A2

=> Flow rate = v * A = constant

=> if 'd' decreases (because A = pi() * d^2 / 4 => A also decreases) then v increases to keep v * A = constant.

Best Regards,