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Old   April 16, 2014, 12:29
Default Some issue with DPM
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John
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Hi everyone,


I have some trouble with discrete phase model in fluent 15, namely no evaporated. All tracked ecaped I attached screen shot on it.


mash 3500000 volumes

Boundary conditions
mass flow inlet 0.3 kg/s 400K
pressure outlet 200000 Pa
total mass fuel 0.066 kg/s (jet-a)

6 injection - Only differing localization

DPM options
tracking parameters - max. number of steps 100000, length scale 0.001m
number of continouis phase interations per DPM iteration - 1
Spatial Discretization, first for all parametres
under-relaxation factors 0.1 for all parameters


First 3000 iterations is compute only cold flow and next turbulence, energy and PDF


I would be grateful for any help


I noticed a mistake in the first screenshot. Flow Rate it should be 0.00011 (0.0011 at present) , number of streams are correct - 10
0.00011x10 x 6(injection) gives the result the assumed 0.0066kg/s - correct me if I'm wrong
Attached Images
File Type: jpg injection parameters.JPG (68.3 KB, 18 views)
File Type: jpg rezid.jpg (86.6 KB, 13 views)
File Type: jpg rezid1.jpg (85.1 KB, 11 views)
File Type: jpg rezid2.jpg (96.5 KB, 10 views)

Last edited by suchy_t; April 18, 2014 at 06:59.
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Old   April 21, 2014, 10:35
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shoeb khan
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to the best of my knowledge

no of steams=10 will not give you 10x of the mass.
Instead of that go in the physical model tab, on the turbulence there and give a value of 10 there.
Try it .

regards
shk
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Old   April 21, 2014, 11:13
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Tkanks for reply,

I do not fully understand which physical model you mean. Can you explain ?

regards,
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Old   April 21, 2014, 11:17
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Quote:
Originally Posted by suchy_t View Post
Tkanks for reply,

I do not fully understand which physical model you mean. Can you explain ?

regards,

I dont have fluent installed on my system so i cannot explain much.

See in your first figure attached there. There is second tab called as physical models.
In that tab there is a turbulence model parameter there. Put that value to 10 and then try, It should work

reagds
shk
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Old   April 21, 2014, 11:28
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Quote:
Originally Posted by shk12345 View Post
See in your first figure attached there. There is second tab called as physical models.
In that tab there is a turbulence model parameter there. Put that value to 10 and then try, It should work

I see. there are no possibilities of entering the parameter specified by you
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File Type: jpg physical model.jpg (44.5 KB, 8 views)
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Old   April 21, 2014, 11:29
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Quote:
Originally Posted by suchy_t View Post
I see. there are no possibilities of entering the parameter specified by you
Sorry buddy
go in turbulence dissipation and t ry
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Old   April 21, 2014, 11:37
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If you mean Discrete Random Walk Model I had already set 10.

The problem is located in a different place, I think.
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File Type: jpg physical model2.jpg (45.9 KB, 7 views)
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Old   April 25, 2014, 06:37
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Maaz Ul Mosaid
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suchy_t

I am facing the same problem now,

Did you find any solution?
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Old   April 25, 2014, 07:19
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unfortunately not,




I only managed to evaporate one of the six vaporizers, bye I do not know the cause of this problem. In this moment I compute over again with different physic model.
Could you write yours boundary condition? inlet outlet, kind of engine ?


regards,
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Old   April 25, 2014, 10:45
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i am modeling coal combustion...

i think this mass decreases because at that inlet conditions of air, it cannot properly burn the fuel.

increasing velocity or temperature may help
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Old   May 3, 2014, 05:49
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I still have the same problem, even if I can evaporate by changing diameter distribution to rosin-rammel the temperature in the model is not changing slightly in comparison with cold flow.
please any advice

regards,
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Old   May 3, 2014, 07:49
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go to

graphics and animations>> particle tracks... >> selection injection name >> summary>> track

and see the report...

i think you will find something
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