Questions about ignition

SZU CYY · May 5, 2019, 07:10

When the ignition energy is set to 0.04 J. Why is sometimes the ignition successuly, but sometimes it fails? What is the factor to effect ignition successfully or unsuccessfully?
Thanks

ywang89 · May 8, 2019, 12:03

Quote:

Originally Posted by SZU CYY

When the ignition energy is set to 0.04 J. Why is sometimes the ignition successuly, but sometimes it fails? What is the factor to effect ignition successfully or unsuccessfully?
Thanks

You need to check if the volume for the energy source is has changed. You can check the maximum temperature in the domain to see if it is big enough like 30000K for engines. Turbulence intensity and the velocity around the spark plug also affect the ignition.

kbansal · May 8, 2019, 12:07

Hi, this is a default value. Generally, this value should come from the user/experiment. The ignition would depend upon this value, mixture fraction and temperature in the domain. If you do not have a well-defined value available and want to make sure that the fuel ignites, you can use a high value for the energy. There is a cut-off temperature which limits the max temperature, no matter what the energy value is.

SZU CYY · May 9, 2019, 12:20

Quote:

Originally Posted by ywang89

You need to check if the volume for the energy source is has changed. You can check the maximum temperature in the domain to see if it is big enough like 30000K for engines. Turbulence intensity and the velocity around the spark plug also affect the ignition.

Thank you, i have understanded it deeply。

SZU CYY · May 9, 2019, 12:23

Quote:

Originally Posted by kbansal

Hi, this is a default value. Generally, this value should come from the user/experiment. The ignition would depend upon this value, mixture fraction and temperature in the domain. If you do not have a well-defined value available and want to make sure that the fuel ignites, you can use a high value for the energy. There is a cut-off temperature which limits the max temperature, no matter what the energy value is.

Thank you very much。

Brilliantur · October 11, 2019, 05:51

Check out whether the volume for energy source changes. Also, keep in mind that velocity and turbulence intensity can affect the ignition.

May 5, 2019, 07:10	Questions about ignition	#1
SZU CYY New Member 陈阳阳 Join Date: May 2019 Location: Shen zhen Posts: 7 Rep Power: 6	When the ignition energy is set to 0.04 J. Why is sometimes the ignition successuly, but sometimes it fails? What is the factor to effect ignition successfully or unsuccessfully? Thanks

May 8, 2019, 12:07		#3
kbansal New Member Join Date: Dec 2015 Posts: 27 Rep Power: 10	Hi, this is a default value. Generally, this value should come from the user/experiment. The ignition would depend upon this value, mixture fraction and temperature in the domain. If you do not have a well-defined value available and want to make sure that the fuel ignites, you can use a high value for the energy. There is a cut-off temperature which limits the max temperature, no matter what the energy value is. __________________ Karan Bansal Senior Research Engineer CONVERGECFD

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Ignition and flame propagation with XiFoam for a few meters long comput. domains	Gloq	OpenFOAM Running, Solving & CFD	1	February 21, 2023 12:22
Map of the OpenFOAM Forum - Understanding where to post your questions!	wyldckat	OpenFOAM	10	September 2, 2021 05:29
Add ignition but combustion does not occur	IColin	OpenFOAM Running, Solving & CFD	3	January 19, 2014 01:43
how does the ignition model initiate main combustion	mepgzzi	Siemens	0	June 23, 2012 14:32
Ignition modeling	Julie Polyakh	Siemens	0	May 20, 2004 08:05

October 11, 2019, 05:51		#6
Brilliantur New Member lucas Join Date: Oct 2019 Posts: 1 Rep Power: 0	Check out whether the volume for energy source changes. Also, keep in mind that velocity and turbulence intensity can affect the ignition.