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December 22, 2011, 08:55 |
combustion doesn't occur need help plz
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#1 |
Member
Boudour
Join Date: Oct 2011
Posts: 34
Rep Power: 14 |
i am working on 2D combustion chamber i achieved the cold flow and now i am working on combustion i used eddy dissipation model to model combustion but the rate reaction still 0 even with mass fraction of co2 and h2o =0
i use k epsilon for turblent model and group injection for diesel C10h22 my conditions boundary are pressure inlet -oulet please does anyone have an idea why the combustion doesn't occur with eddy dissipation model |
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December 26, 2011, 14:38 |
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#2 |
Member
Mosi Owa
Join Date: Nov 2011
Posts: 35
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What is your initial temperature? Do you initialize your domain with a high temperature or not?
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December 26, 2011, 20:01 |
hi
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#3 |
Senior Member
shoeb khan
Join Date: Nov 2011
Posts: 179
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try to run the simulation for various higher temperatures.
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December 27, 2011, 09:28 |
re: cpmbustion doesn't occur
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#4 |
Member
Boudour
Join Date: Oct 2011
Posts: 34
Rep Power: 14 |
first of all thank you for replying
i initialize my temperature to 300 k but the temperature in the combustion chamber is about 900 k isn't enough for the combustion of diesel i even try the patch but nothing that happens |
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December 27, 2011, 09:33 |
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#5 |
Member
Boudour
Join Date: Oct 2011
Posts: 34
Rep Power: 14 |
thank's for replying
my initial temperature is about 300 k |
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December 27, 2011, 11:01 |
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#6 |
Senior Member
shoeb khan
Join Date: Nov 2011
Posts: 179
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No combustion reaction occurs at 300
use higher temp as around 600- 1000 and see the various products |
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December 27, 2011, 14:57 |
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#7 |
Member
Mosi Owa
Join Date: Nov 2011
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December 28, 2011, 03:13 |
response
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#8 |
Member
Boudour
Join Date: Oct 2011
Posts: 34
Rep Power: 14 |
this is the details of my case
•Select k-epsilon model (realizable) under Viscous Model •Under Species & Transportation I select "Species Transport", Mixture properties "diesel-air" with everything else unchanged. volumetric : eddy dissipation model •Now I set up DPM. Enable "interaction with continous phase", enable "unsteady particle tracking", Number of Continous Phase Iterations per DPM Iteration set to 200. ?under Physical Models i enable "DRoplet Collision" and "Droplet Breakup Model". Under Break up constant I set "Breakup Parcel to 50". ?Under Tracking Tab I set Drag Law to "dynamic-drag" ?Particle time step set to 0.00001 •Injections: I create an injection. "group". Particle Type "Droplet". Material "Diesel Liquid". Flow Rate to be 3.22e-4 kg/s. crank angle 700, Stop Time 720.temperature diesel 310k ?Under Turbulent Dispersion I enable "Discrete Random Walk Model" and "Random Eddy Life" •Under Solve-> Controls -> Solution I leave default settings and select OK •Now I select Initialize.to 1600k. when the iteration finished i go to track particle :and i have this summary Fate Number Elapsed Time (s) Injection, Index Min Max Avg Std Dev Min Max ---- ------ ---------- ---------- ---------- ---------- -------------------- -------------------- Evaporated 831 3.989e-02 4.000e-02 3.995e-02 0.000e+00 injection-0 0 injection-0 0 (*)- Mass Transfer Summary -(*) Fate Mass (kg) Initial Final Change ---- ---------- ---------- ---------- Evaporated 3.434e-08 0.000e+00 -3.434e-08 (*)- Energy Transfer Summary -(*) Fate Energy (J) Change of Energy (J) Initial Final Sensible Latent Total ---- ---------- ---------- ---------- ---------- ---------- Evaporated -9.046e-03 0.000e+00 -1.468e-03 1.051e-02 9.046e-03 number tracked = 7297, escaped = 0, aborted = 0, trapped = 0, evaporated = 0, incomplete = 7297, coalesced = 0, shed = 0, splashed = 0 one thing that i don't understand is why the evaporated ones are 0 and the incompleted ones are 7297 still nothing happen |
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December 28, 2011, 14:01 |
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#9 |
Member
Prakash Ghose
Join Date: Dec 2011
Posts: 34
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check the arhenius parameters from literature
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December 29, 2011, 03:06 |
re
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#10 |
Member
Boudour
Join Date: Oct 2011
Posts: 34
Rep Power: 14 |
thank you for replying
eddy dissipation model doesn't take in account the arhenus chemical reaction are you talking about finte rate / eddy disspiation model ? |
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