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-   -   DMP problem (http://www.cfd-online.com/Forums/fluent/31805-dmp-problem.html)

zwdi July 10, 2003 21:56

DMP problem
 
Dear all, I use DMP model to simulate the dye movement. Surprisingly, I got the result of "evopated=100" state of the dye. The property of the dye is "inert". There is no energy transfer between these two phase(water and dye). I set the density of the dye similar to water. What cause this happen? Any answer will be very appreciated.Thanks. ZWDI

alex July 10, 2003 22:47

Re: DMP problem
 
hi

Did you inactive the custom law 1 Inert Heating?

It seems to me that you should do it

Regards

Alex

kevin July 11, 2003 10:31

Re: DMP problem
 
It seems inactiving law 1 doesn't help. There should be some other settings, it is really confusing at this point.

alex July 11, 2003 12:32

Re: DMP problem
 
HI

Could you please check these parameters under:

define>materials>create and change type the name of your material (i.e. dye) type the density constant type the specify heat constant type the thermal condutivity constant

Often times, fluent assumes values for the last two parameters, which could be unappropiate for your case!!

Regards

Alex


zwdi July 11, 2003 20:34

Re: DMP problem
 
Thanks for response. I didn't active energy. And for the material property, only density is needed for inert particles. Seems that I didn't make one error in that point.

alex July 11, 2003 21:20

Re: DMP problem
 
HI

I know that you don't active energy. However, I have found that fluent assumes those values. Evenmore, the code gives you a messege that termal coeeficient was required. If you recognize this message by pressing Ok, Fluent takes some values from a database. Therefore, make sure that fluent store appropiated values.

For setting these values you have to use the text comand not the display comand.

Type

define>material>change then follow the instructions by typing Y or N and the values

Regards

Alex Munoz

kevin July 12, 2003 08:35

Re: DMP problem
 
Hello

Thanks your message. After changing Cp and thermal conductivity, dye is still evaporated. When go to define>materials, it seems that only Cp and thermal conductivity can be changed. Is there any other parameters needed changing? Thanks again.

Alex Munoz July 12, 2003 13:58

Re: DMP problem
 
Hi

At this point, I don't know what is causing this phenomena. I have read simmilar cases before in this forum. I wonder what is your particle diameter, and also which Fluent version are you using.

Please let me know this information!!

Regards

Alex Munoz

zwdi July 12, 2003 17:55

Re: DMP problem
 
I set the particle(dye)diameter is the same as water diameter. And I use Fluent 6.1. Thanks,

hedonists July 22, 2003 14:36

Re: DMP problem
 
I meet the same problem also. Whatever material I use, when particles are below 10nm, it simply evapolate (the temperature is only 300K). This did not happen before, but it becomes so after my university renew the FLUENT licence this April.

hedonists July 22, 2003 14:45

Re: DMP problem
 
I think it's a problem of Fluent 6.1. It worked well in FLUENT 6.0.

kevin July 31, 2003 15:49

Re: DMP problem
 
Do you try to solve it with FLUENT 6.o again? I tried it, but it was still evaporated.

hedonists August 11, 2003 22:43

Re: DMP problem
 
Yes, I tried in 6.0. It worked well


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