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Old   February 18, 2017, 01:14
Lightbulb Problems with Biomass Gasification
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Chalumpol
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Hello Everyone..

I'm researching about Biomass Gasification in downdraft gasifier in Thailand and i would like to simulate the temperature distribution and mole fraction in the gasifier with CFD and i'm newbie with it.

I found a paper that is closed to my work. the link is https://www.researchgate.net/publica...IT_BUNCH_WASTE.I have read that paper and i try to study from that. My model is on below of the paragraph.

Capture.PNG

My model is refer to that paper, 2D Realization k-e model, with steady state. i used species transport with 9 species as CH4,CO,N2,H2O,O2,C<S>(use in particle surface reactions),H2,CO2,and Volatiles. i used species transport with finite rate/eddy dissipation and the reaction i add in reaction tab is

Volatile decomposition reaction
1. Vol + 0.174O2 + 0.457H2 ---> 0.268CO + 0.371H2O + 0.357H2 +0.003N2
Gas Phase Reaction
2. 2CO + O2 ---> 2CO2
3. 2H2 + O2 ---> 2H2O
4. CO + H2O ---> CO2 + H2
Particle Surface Reactions
5. C<s> + O2 ---> CO2
6. 2C<s> + O2 ---> 2CO
7. C<s> + 2H2 ---> CH4
8. C<s> + H2O ---> COH2

the volatiles which is calculated from coal calculator is balanced from the producer gas, so I have to add hydrogen to balance the equation.

Capture2.PNG

boundary condition:
drying ---> 373k
pyrolysis ---> 673k
gasification ---> 1073k
reduction ---> 573k
air inlet(mass flow rate) ---> 1.68e-3 kg/s (2 nozzles)
fuel inlet (mass flow rate) ---> 2.78e-3 kg/s

My surface body is air. and all the wall temp is 300 kelvin with the coefficient of heat transfer 10 W/m2. and internal emissivity is 0.6. The solution control is set as default. And solution initiation is hybrid.The solution method is used SIMPLE. Least-squared Cell based,the pressure methods is PRESTO!, and the others are First Order Upwind.

When i run calculations, the result goes to 9 iterations and stopped running with the error "Error: received a fatal signal (Segmentation fault). Error Object: #f". and the value at all of the species are zero.

Capture4.PNG

Capture3.PNG

The question is how can i check the cause of the error and how can i solve it?

Thank you for your kind answer.
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Old   August 29, 2017, 03:57
Default problem with chemkin
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Nityanand Hiraprasad Kushwaha
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since you mentioned the paper you are following I got interested in your query because I am also doing a simulation using same the paper but I am not getting the required solution. Also conc. of CO and H2 are main species to focus upon but without chemkin I am getting nothing.
can u please help in chemkin?
Also iam uploading meshing pics and convergence pics.conver.txt
mol. conc. of CO
CO conc.jpg

PLEASE HELP ME IN CHEMKIN!
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