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-   -   Cyclone Tangential Velocity ... (http://www.cfd-online.com/Forums/fluent/48880-cyclone-tangential-velocity.html)

Abdul July 28, 2008 02:24

Cyclone Tangential Velocity ...
 
I am Modeling a Cyclone with mass flow inlet and static pressure gas outlet. I am not modelling the solid outlet as of now. I have used RSM model, DPM, 1st order upwind with a residual convergence upto 1e-06. When i plot the tangential velocity along the axis of the cyclone, the tangential velocity is highest near the axis and it is reducing in the radial direction. Whereas the experiments and some literatures shows that the tangential velocity is minimum at the center and it increases radially upto vortex. But, Some other literatures shows simillar to my case. Can anyone throw some light on it???

CDE July 28, 2008 19:01

Re: Cyclone Tangential Velocity ...
 
Firstly, you need to use 2nd Order UPWIND for this type of flow. Also, enable the Radial Equilibrium distribution on the pressure outlet for the vortex finder if you haven't already done so.

I don't understand you question about the velocity. Are you confusing Tangential velocity with Axial velocity in your question? Tangential velocity must be zero at the core of the swirling flow.

sushilkumar August 13, 2008 00:07

Re: Cyclone Tangential Velocity ...
 
I am Modeling a Cyclone with mass flow inlet and static pressure gas outlet. I have used quick system power law with coupled solver and CFL no. of 10, When i plot the tangential velocity along the axis of the cyclone, the tangential velocity is highest near the axis and it is reducing in the radial direction. Whereas the experiments and some literatures shows that the tangential velocity is minimum at the center and it increases radially upto vortex. i have analysed around 15 no. of cyclones out of it 2 no. of cyclones i am getting tangential velocity maximum at the centre which is reverse case of analysis did uptill now. why is it happnening i am not understanding. can any body help me. i have used boundary condition of 15 m/s to inlet and -1000 pa pressure at outlet. same conditions were applied to lapplue model and other cyclones. but i am geting opposite result for this 2 types of cyclones


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