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-   -   Help for Discrete Phase Model (http://www.cfd-online.com/Forums/fluent/39742-help-discrete-phase-model.html)

MANOJKUMAR February 21, 2006 04:10

Help for Discrete Phase Model
 
Hello I setting the injection in 10m length and 2m dia. velocity of air is 1 m/s and injection setting is 0.3 dia ,0.0059 kg/sec flow rate and velocity is 100m/s but there is message when run. Tracked 100 , escaped=0, aborted=0, traped=0,evaporated =0 and incompleted is =100. I think there is no combustion so how to started combustion please help me.

HS February 21, 2006 04:18

Re: Help for Discrete Phase Model
 
I don't know about combustion, but "incomplete" in this message means that your settings are not enough to follow the entire particle flow path within the domain. Try to increase the maximum number of steps in the tracking parameters in the DPM panel in FLUENT.

Hope this helps!

/Henrik

MANOJKUMAR February 21, 2006 04:45

Re: Help for Discrete Phase Model
 
Thanks

I used Light Diesel oil as a fuel. If there is any tutorial or any material for setting the injection related with liquid fuel then please send me. my e-mail is ms_project05@rediffmail.com

Marina February 21, 2006 04:57

Re: Help for Discrete Phase Model
 
I think your problem is in the air inlet temperature ... maybe .. the inlet air temperature = ??? the inlet fuel temperature = ??? The inlet fuel temperature should be defined as the temperature at which vaporization begins.

If the inlet air temperature is low, let's say about 20C, you can not ignite your fuel.

When you initialize your solution Solve - Initilaize -initialize you have to give initial value for temperature about 2000 K. That initial condition acts as a numerical "spark" and ignite the fuel-air mixture (in case your inlet air temperature is low)

or you can do it with Solve- Initialze-Patch ...

Hope it helps !

MANOJKUMAR February 21, 2006 08:41

Re: Help for Discrete Phase Model
 
Thanks Marina

my air temperature is 650K and fuel is 303K. and at initilization temp is same as air. How the patch is done. In my case when i select Patch then only flue gas is shown when set temperature.Any help for setting the Patch. Once again thenks. MANOJ KUMAR

James Willie February 21, 2006 09:51

Re: Help for Discrete Phase Model
 
Hi,

Hope you were able to provide accurate values for the thermophysical properties of the fuel? What is the boiling temperature of the fuel? Was your evaporation also very accurate? Was your fuel in the fluent database?

Which combustion model are you using? For most combustion models-eg. finite rate/eddy dissipation model, you need to have products in your combustion zone for reaction to start. So in the this region, try to patch products as well. So you will patch products and temperature in the combustion zone.

To do the patching, goto Adapt>Region and enter the coordinates of the region you wish to patch. Do the patching close to the flame holder.....but it should be in the combustion chamber, where combustion is likely to take place. Assign values for x, y and z to cover the region you wish to patch.

After, click Mark.

Then goto Solve>Initialize>Patch and click on the mark region in the right lower corner and from the left size, click on temperature and set the value to say 1600 and click patch and do likewise for products.

Then do a few iterations to see if you have a reaction.

Hope this helps.

James


GANESH February 22, 2006 01:13

Help for Discrete Phase Model
 
Iam modeling calciantion of CaCO3 in a cyclone calciner. iam using DPM modelling for coal combustion,but i dono how to model calcinatiion reaction of CaCo3 using the DPM approach.If u got any idea let me . Thanku ,GKV.


James February 22, 2006 03:30

Re: Help for Discrete Phase Model
 
Hi,

Sorry I cannot help you. What i did was using DPM for liquid fuel-diesel combustion simulation. What you have is a solid fuel and so i am not very familiar with this one. Try to look for a tutorial from the Fluent manuel.

James


MANOJKUMAR February 22, 2006 05:47

Re: Help for Discrete Phase Model
 
Thanks James I used Liquid fuel-oil-air given in Fluent data base and also in Injection setting. But the fuei-oil-air written is C19H30. when I made PDF file and selected composition then there is no C19H30 so which is selected. If u have any tutorial about liquid fuel for setting injection then please send me. I read tutorial given by Fluent which is Liquid fuel combustion. I solved that problem. But my case dia is 350 mm air inlet. and 25 litre/hr fuel is used. How I can find the velocity of air,fuel, dia of fuel. if don,t mind can I asked ur e-mail ID so i can give my problem. my e-mail is ms_project05@rediffmail.com MANOJKUMAR

satish February 23, 2006 02:54

Re: Help for Discrete Phase Model
 
hi manoj i hv done dpm using kerosene can u send me the details of ur problem so that i can help u. Do u hv the reaction data for the diesel.

MANOJKUMAR February 23, 2006 06:42

Re: Help for Discrete Phase Model
 
Thanks for giving postive response.

I do not know ur e-mail ID so Please send me ur e-mail ID.So I can send my problem in detals. My e-mail is ms_project05@rediffmail.com.I am using diesel as fuel but I want to know how u have set ur problem.I just check the temperature distribution of the model so I can use any fuel.In my case I have dia 350 mm of air and fuel flow rate 25 liter/hr. and I am setting the injection. For setting the air and fuel there is requierd the velocity and other parameter so any method to find all this details.Can u give me ur case and data file and PDF file. Thanks

s567d March 15, 2011 08:29

Droplet evaporation;heat and mass transfer;two way interaction; coaxial fuel and air flow; known air velocity and fuel mass flow rate;
1) How can I model for a fuel which is not in the list of fluent (say, Iso-propyl alcohol [IPA])? If the fix is not regular.
2) I want to use UDF for heat and mass transfer. Can any one tell where to add udf. No option is available on my software or am I doing wrong?
3) Can I know the droplet phase velocity, diameter, temperature, etc., other than droplet trajectory. Also, droplet extinction time or evaporation rate. Then, How? I not able to get any DPM info other than droplet trajectory. Also the message from fluent was that Heat and mass transfer is incomplete.


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