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Old   January 6, 2012, 12:23
Default combustion
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Boudour
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hello everybody
iam simulating 2D combustion chamber of a diesel engine i managed to get the combustion using a patch in temperature
i have used volumetric reaction finite rate / eddy dissipation model
the temperature rises until 1800k but pressure didni't it still const as the cold flow arround 48 bars (with combustion 80 bars)


should i patch pressure too ???????

do you have any idea how can i solve it
any help will be appreciated
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Old   January 6, 2012, 13:37
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shoeb khan
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hi
can you share your mesh pic and contour plots of temp, vel, pressure so that your problem can be more defined.
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Old   January 8, 2012, 06:07
Default re: combustion
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thank you for your reply
the picyures are joined

Last edited by roukaia; January 9, 2012 at 13:52.
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Old   January 8, 2012, 09:39
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i think that your solution is not totally converged as the velocity and temperature profile are quite random showing no resembelence.

About pressure , pressure should increase inside the domain. There must be something that you are not considering may be check your mesh again and your geometry. I guess that in diesel engine dynamic mesh should be used as one valve will open and that other will close that will result in increase of pressure inside the domain.

Correct me if i am wrong

shk
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Old   January 8, 2012, 14:17
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hello
thanks for your response
the countours are taken in the compression stroke, after injection of diesel both of the valves are closed . the opening and the close of valves are taken into acount as you said

what do you mean by there is no resemblence beteween velocity and temperature
what should be instead of this countours
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Old   January 9, 2012, 00:02
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hi
I think that the pressure and velocity should be symmetrical or symmetric at some domain inside the computational grid.
Also the increase in pressure in the chamber is no0t due to closing of the valves it's because of the compression generated by the piston inside the combustion chamber.

Kindly see into account this phenomena.
Also post the contour of the species so that the problem can be more clear .

Shk
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Old   January 9, 2012, 10:44
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Hi
for pressure you can try to initialize the solution from all zones and put pressure there equal to the guage pressure .
I hope that will solve the problem.

shk
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Old   January 9, 2012, 14:23
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thank's khan for your help it is so kind of you
the countours of species that you need to see are joined
for gauge pressure it is set to 0 pa
operation pressure 103125 pascal

absolute pressure = guauge pressure + operating pressure =103125 pas
my initialisation is 0 pascal= gauge pressure

thank's khan

Last edited by roukaia; January 10, 2012 at 13:40.
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