Turbulent kinetic energy for accelerating fluid (nozzle)

heksel8i · September 24, 2013, 08:17

Hey!

Assuming a high pressure chamber with a converging or converging-diverging nozzle, the fluid is accelerating on its way out. While determining the turbulence boundary conditions for the nozzle inlet, a question arises which mean velocity should be used in kinetic energy equation k=(3/2)(UI)^2. Intensity is probably low, around 1%?

Personally I guess after some simple simulations that mean velocity between inlet and throat could be appropriate. (v_throat - v_inlet)/2.

heksel8i · September 30, 2013, 08:26

It is also interesting to calculate the parameter values with the initial velocity in a chamber, which is really really slow compared to the throat velocities. Pressure and velocity field results do not change so much but of course turbulence quantities change drastically...

Any ideas?

September 24, 2013, 08:17	Turbulent kinetic energy for accelerating fluid (nozzle)	#1
heksel8i Member hekseli Join Date: Mar 2013 Posts: 49 Rep Power: 13	Hey! Assuming a high pressure chamber with a converging or converging-diverging nozzle, the fluid is accelerating on its way out. While determining the turbulence boundary conditions for the nozzle inlet, a question arises which mean velocity should be used in kinetic energy equation k=(3/2)(UI)^2. Intensity is probably low, around 1%? Personally I guess after some simple simulations that mean velocity between inlet and throat could be appropriate. (v_throat - v_inlet)/2.

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September 30, 2013, 08:26		#2
heksel8i Member hekseli Join Date: Mar 2013 Posts: 49 Rep Power: 13	It is also interesting to calculate the parameter values with the initial velocity in a chamber, which is really really slow compared to the throat velocities. Pressure and velocity field results do not change so much but of course turbulence quantities change drastically... Any ideas?