DPM or MultiPhase - Criteria - Help

jpinho · September 1, 2009, 10:56

Hello,

I am getting confused of the main differences of these 2 models in Fluent.

As far as I know, for spray drying modelling, the DPM would fit better. There are various models on the tutorials and user guide. On the other hand I have seen various articles and cases where the multiphase model is used.

If I am modelling the injection of particles that will interact with a primary phase with mass and heat transfer, what would be the best model to track those particles and to study how they interact (for instance evaporation) with the main phase?

regards
jpinho

davidhap · October 18, 2009, 03:16

i've faced the same problem you had. i used the function DEFINE_DPM_HEAT_MASS() to compute heat and mass transfer, but there are a lot of interior mistakes. and the term of mp is not the mass of all particles in a cell given in this function. someone used UDM to describe these variables. hope this will help! and we can communicate for further study if you want. my email: david_chiyi@yahoo.com

AMusteykis · January 18, 2010, 11:55

Hello, pinho and david!
I'm modeling kerosene-air evaporating and mixing device and face some troubles with it. I see you had some experience with UDF for DPM may be it'll help in my case.
My problem is so:
Kerosene liquid is injected into swirling air flow.
Mass flow rates: kerosene - 5 g/s, air - 83 g/s. Temperatures: kerosene - 300 K, air - 611 K. I read that discrete phase model is suitable for such problem (I think volume fraction of kerosine is not more than 10%).
In this case I chose spherical liquid kerosene droplets of diameter 1 mm.
When I'm trying to calculate this case it seems that all of particels reach the wall of the device and then nothing happens but they should evaporate from it. Temperature of the wall is also 611 K. I've tried all wall B.C. for such model but it didn't help. Thermodynamic properties of liquid kerosene droplets were set up right.
May be I should use some UDF to describe specific aspects of problem or I can't understand this model at all?
Sorry for interrupting you but I think for Fluent users it's useful to keep contact and share each other progress especially if they are modeling quite the same.

cheers

September 1, 2009, 10:56	DPM or MultiPhase - Criteria - Help	#1
jpinho New Member pinho Join Date: May 2009 Posts: 22 Rep Power: 16	Hello, I am getting confused of the main differences of these 2 models in Fluent. As far as I know, for spray drying modelling, the DPM would fit better. There are various models on the tutorials and user guide. On the other hand I have seen various articles and cases where the multiphase model is used. If I am modelling the injection of particles that will interact with a primary phase with mass and heat transfer, what would be the best model to track those particles and to study how they interact (for instance evaporation) with the main phase? regards jpinho

October 18, 2009, 03:16	It's difficult!	#2
davidhap New Member david Join Date: Mar 2009 Posts: 6 Rep Power: 17	i've faced the same problem you had. i used the function DEFINE_DPM_HEAT_MASS() to compute heat and mass transfer, but there are a lot of interior mistakes. and the term of mp is not the mass of all particles in a cell given in this function. someone used UDM to describe these variables. hope this will help! and we can communicate for further study if you want. my email: david_chiyi@yahoo.com

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January 18, 2010, 11:55		#3
AMusteykis New Member Anton Musteykis Join Date: Sep 2009 Location: Saint-Petersburg, Russia Posts: 12 Rep Power: 16	Hello, pinho and david! I'm modeling kerosene-air evaporating and mixing device and face some troubles with it. I see you had some experience with UDF for DPM may be it'll help in my case. My problem is so: Kerosene liquid is injected into swirling air flow. Mass flow rates: kerosene - 5 g/s, air - 83 g/s. Temperatures: kerosene - 300 K, air - 611 K. I read that discrete phase model is suitable for such problem (I think volume fraction of kerosine is not more than 10%). In this case I chose spherical liquid kerosene droplets of diameter 1 mm. When I'm trying to calculate this case it seems that all of particels reach the wall of the device and then nothing happens but they should evaporate from it. Temperature of the wall is also 611 K. I've tried all wall B.C. for such model but it didn't help. Thermodynamic properties of liquid kerosene droplets were set up right. May be I should use some UDF to describe specific aspects of problem or I can't understand this model at all? Sorry for interrupting you but I think for Fluent users it's useful to keep contact and share each other progress especially if they are modeling quite the same. cheers