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-   -   problem in MRF and DPM method (http://www.cfd-online.com/Forums/fluent/28596-problem-mrf-dpm-method.html)

you June 11, 2001 04:33

problem in MRF and DPM method
 
Hi, All friends,

I am calculating drops distribution in a baffle tank with rotating impeller (Fig. 16.2.3, pp.16-7, Fluent manual) by using the multiple reference frame in conjunction with the discrete phase model. I find the drops DPM concentration near wall is extremely high (order of 10^6 kg/m^3). Please tell me why this happens and how to get a reasonable result. Thanks you very much for your help.

I am looking forward to your reply.

With best regards,

You

Alain June 12, 2001 07:13

Re: problem in MRF and DPM method
 
Hello

in my point of view there is some problems in your simulation :

1) first of all you should check that you use the absolute reference frame for trajectories calculation (you will have non physical results if you don't)

2) DPM is better suited for flow with an inlet and outlet, at last for particle. If you model a flow where particle settled your results will depend on the number of lagrangien iteration you use and it can't be very difficult to reach a real steady state solution. Remember that you inject particle with a certain mass flow rate, if there are no outlet for particles the concentration will be infinite (that's why you have 10E6 kg/m3 of particles at wall).

You could try an Euler/euler multiphase model

best regards

Alain


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