Some issue with DPM
 

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

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

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

I see. there are no possibilities of entering the parameter specified by you

Sorry buddy
go in turbulence dissipation and t ry

If you mean Discrete Random Walk Model I had already set 10.

The problem is located in a different place, I think.

suchy_t

I am facing the same problem now,

Did you find any solution?

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,

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

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,

go to

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

and see the report...

i think you will find something