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-   -   DPM of cyclone (http://www.cfd-online.com/Forums/fluent/34645-dpm-cyclone.html)

fpingqian September 19, 2004 09:30

DPM of cyclone
 
I am majoring in cyclone separator numerical simulation by means of Fluent 6.1. In my procession of simulation, I have met some questions in DPM. Firstly,I hope you will give some help to me. In my calculation, after the gas flow field of cyclone has been converged, 10000 particles (density is 2750kg/m3) were injected into the domain, and the particle track is steady in my case. Additionally iteration with the continuous phase was selected (i.e. two-way coupling). But after the DPM has been converged, the gas flow field is unchanged comparing to the gas flow field without considering the iteration with continuous phase. Secondly,how do i abtain the DPM concentration distribution in Display? Thank you for your information!

Jan Rusås September 23, 2004 12:39

Re: DPM of cyclone
 
I can see two reasons for why the flow field is not changed.

1) Do you use a very low under relaxation factor, for the discrete phase solution.

2) If you mass loading is very small then would the impact on the flow field also be very small. How large is the mass flow of the particles and the flow

How many two-way coupling did you use?, have you checked all mass balances.

fpingqian September 23, 2004 20:26

Re: DPM of cyclone
 
Thanks for your responding to my questions! In my calculation, turbulence model is RSTM, the under relaxation is by default except momentum which is 0.5.Additionally, the inlet solid loading in my model is 2g/m^3(gas). How many two-way coupling did you use? i have iterated about 13000 times, and the mass balance is abtained. would you tell me the reason again? thanks a lot!

Jan Rusås September 27, 2004 04:35

Re: DPM of cyclone
 
Would you expect throwing a small sand corn into a huricane that the sand corn would change the huricane! (I think only in chaos theory) I think 2g/m^3 is so small that it would not change the gas flow field. I have not calculated it for your case, but there are some general global guidelines for predicting if there is a one-way or two way coupling for gas-particle flow. Try to check that.

Jan


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