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Two-mixture-fraction in Non-Premixed Combustion Model |
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November 14, 2012, 01:41 |
Two-mixture-fraction in Non-Premixed Combustion Model
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#1 |
New Member
Nurul
Join Date: Sep 2012
Posts: 15
Rep Power: 14 |
Hello everybody,
I want to simulate coal gasification by using Non-Premixed Combustion and DPM in 3D Model. I've tried use single-mixture, but char conversion only 20%. In the literature, Fluent User's Guide, using two-mixture-fraction more accurate than single-mixture. So, I want to use two-mixture-fraction. But, I can't create PDF table and appeared "Calculation aborted due to critical error". Why it happened? Can you tell me about the constraints for using two-mixture-fraction? Anyone have paper/journal/tutorial guide which contains solution of coal gasification by using Non-Premixed model? Thankyou |
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March 29, 2014, 12:11 |
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#2 |
Member
Maaz Ul Mosaid
Join Date: Jan 2014
Location: Pakistan
Posts: 32
Rep Power: 12 |
Try to decrease Number of mean mixture fraction points to 9-15
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March 30, 2014, 08:02 |
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#3 |
New Member
Michael Hilton
Join Date: Feb 2014
Posts: 8
Rep Power: 12 |
hi Maaz
i'm having the same problem today and i have been unable to work out the problem. Decreasing the micture fraction points didn't help. Is there any other ways to fix this as it's very urgent thank you |
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April 3, 2014, 13:06 |
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#4 |
Member
Maaz Ul Mosaid
Join Date: Jan 2014
Location: Pakistan
Posts: 32
Rep Power: 12 |
no I am not experienced user. Sorry , cant help you
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April 17, 2015, 01:11 |
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#5 |
Member
sanjeet Limbu
Join Date: Mar 2015
Posts: 91
Rep Power: 11 |
I am using the ignition delay model for combustion by compression stroke of cylinder... simulation to rapid compression machine. The mixture fuel is inside the cylinder compressed at 30 millisec.
I am able to run the dynamic mesh using the chem kin file for combustion . I got some results... But I expected the combustion to make temperature rise, but i am getting early rise in temperature, while fuel also dispense early than compression end If possible can u suggest if I entered any wrong input in initialization or model dialog box The dynamic mesh used to show compression- for 30 millisec and combustion is expected after 30 millisec Problem- Everything related to combustion seem start early before compression stroke end. Unable to get temperature/pressure rise after compression stroke at 30 ms The mole fraction for n-heptane start from 0.0025, instead of the 0.00562 I entered in boundary condition for the model. I am using N2/O2/nC7H16: 89.5/10.307/0.00562 as fuel mixture I am getting early combustion - seeing P and T graph from CFD post I checked by change in initialisation mean mixture fraction 0 and 1, so for 298K as initial temp the mean mixture fraction is needed as zero, if I enter mean mixture fraction as 1- the temperature jumps to the PDF calculated 1100K. Since the fuel mixture become nil if I use the mean mixture fraction as zero. Pl help how to keep both temp also 298 K and fuel mixture as entered in boundary condition PDF calculation. Please suggest how to set up the model ascombustion happens start early CFD post results |
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April 17, 2015, 03:25 |
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#6 |
New Member
Nurul
Join Date: Sep 2012
Posts: 15
Rep Power: 14 |
I'm not experienced user. But, If I could give a comment. May it is because the composition of your fuel mixture is not appropriate. N2/O2/nC7H16: 89.5/10.307/0.00562 is used. I think, the ratio O2/nC7H16 is too high, so the nC7H16 is burn completely and rapidly. Check the result's composition, isn't it. I'm sorry, I can not help you.
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Tags |
dpm, non-premixed, single-mixture-fraction, two-mixture-fraction |
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