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Old   September 22, 2003, 11:56
Default low concentration multiphase
  #1
zwdi
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Hello everyone,

I model very, very low concentration multiphase flow. The concentration of phase 2 is around 10e-07g/cm3, which is got from experiments. For numerical model, I use mixture multiphase flow(not Euler model). The difference between experiments and numerical model is very large. Does anyone know if this multiphase model in Fluent can simulate my case?(very low concentration)

Thanks a lot.

Zwdi
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Old   September 23, 2003, 03:52
Default Re: low concentration multiphase
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Ben
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You would be better in my opinion to use the Euler Lagrangian approach (discrete phase model), which is suitable if your volume fraction of the secondary phase is less than 10-12%. Using this approach you can inject in individual particle streams. The muliphase models are really more suitable for higher volume fraction (approx >20-30%).

Hope this helps
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Old   September 23, 2003, 05:15
Default Re: low concentration multiphase
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thomas
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hey, Effectively the euler langragian seems to be the best and the right solution. Also for accuracy you should use the double precision solver of Fluent (fluent 2ddp or 3ddp). thomas.
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Old   September 23, 2003, 10:32
Default Re: low concentration multiphase
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zwdi
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Hello Ben and Thomas,

Thank you very much. What I am simulating is air pollution in street canyon. I tried DPM model before. My sencond phase is sodium fluorescein(its diameter is 0.9e-09m, same order of water molecular diameter.Density is simlar to water. It can be solved in water. It was injected into street canyon in solution form. So, acturally high concentration solution was injected into street canyon and was diluted due to the wind above the roof). The problem I met when using DPM model is that I got EVAPORATE for all the tracked particles.(I didn't active energy option.The particles are inert) Thus, I couldn't get the concentration value in street canyon. Due to that reason, I changed to multiphase model, hoping it can work well.

If you can take some time to think over my problem I met in DPM model, I am very appreciated for your help.

By the way, I have tried double precision solver already. But its result is the same as single precision slover.

Thanks again.

Zwdi
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Old   June 1, 2009, 17:10
Default Concentration of DPM
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Saima
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Saima is an unknown quantity at this point
Hello everyone,

Can anybody define Concentration in DPM?

I m very thankful 2 u.

Regards,
Saima
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