Problem diverges: Scalar/Species transport equation

milad21 · August 27, 2016, 10:01

Hi
my calculation becomes diverged at 720 CA.
This is the problem ===> Problem diverges: Scalar/Species transport equation, variable
I changed scalar and species transport equation terms in under relaxation factors but still doesn't work.
How can I fix it?

firemann · September 22, 2016, 07:18

Did you use general gas phase reactions module for simulation?

iman.pourmousavi · August 13, 2018, 06:28

Quote:

Originally Posted by firemann

Did you use general gas phase reactions module for simulation?

Hello
Im using GGPR and i face this error .could you help me?
Iman

swerner0711 · October 5, 2018, 07:44

Hey Iman,
maybe I could help You.

Where do You start simulating, at 0°CA or 180°CA (or maybe even somewhere else)? I had a divergence right when the exhaust valve opened at some point and could solve it with using a smoothening function. maybe that's the case with Yours as well, does the intake valve open at 720° and cause the diversion?

iman.pourmousavi · October 8, 2018, 06:33

Hi Stephan
Actually the simulation started at -145.3 CA.

swerner0711 · October 8, 2018, 07:13

So you start at -145.3° CA at TDC (?), at 574.7° CA you have another TDC and an intake stroke starts. Maybe the intake valve closes at 720°? Did you Use any special functions around 0° like a smoothener for pressure/temperature?

Why do You simulate more than 4 strokes?

Dennniem · November 20, 2018, 07:39

I have a similar problem.
My simulation is diverged around 760CA (intake stroke 526CA - 772CA).
I have already set a smoothing function (100 iterations) for temperature and pressure.
How can I solve this problem? Increase the iterations of the smoothing function?

Best regards

August 27, 2016, 10:01	Problem diverges: Scalar/Species transport equation	#1
milad21 New Member saeid Join Date: Aug 2016 Posts: 1 Rep Power: 0	Hi my calculation becomes diverged at 720 CA. This is the problem ===> Problem diverges: Scalar/Species transport equation, variable I changed scalar and species transport equation terms in under relaxation factors but still doesn't work. How can I fix it?

October 5, 2018, 07:44	What happens at 720°	#4
swerner0711 New Member Stephan Werner Join Date: Sep 2018 Posts: 6 Rep Power: 8	Hey Iman, maybe I could help You. Where do You start simulating, at 0°CA or 180°CA (or maybe even somewhere else)? I had a divergence right when the exhaust valve opened at some point and could solve it with using a smoothening function. maybe that's the case with Yours as well, does the intake valve open at 720° and cause the diversion?

October 8, 2018, 07:13		#6
swerner0711 New Member Stephan Werner Join Date: Sep 2018 Posts: 6 Rep Power: 8	So you start at -145.3° CA at TDC (?), at 574.7° CA you have another TDC and an intake stroke starts. Maybe the intake valve closes at 720°? Did you Use any special functions around 0° like a smoothener for pressure/temperature? Why do You simulate more than 4 strokes? iman.pourmousavi likes this.

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September 22, 2016, 07:18		#2
firemann New Member nieman Join Date: Sep 2016 Posts: 1 Rep Power: 0	Did you use general gas phase reactions module for simulation?

October 8, 2018, 06:33		#5
iman.pourmousavi New Member iman pourmousavi Join Date: Sep 2013 Location: iran Posts: 5 Rep Power: 13	Hi Stephan Actually the simulation started at -145.3 CA.

November 20, 2018, 07:39		#7
Dennniem New Member Dennis Niemann Join Date: Oct 2018 Location: Germany Posts: 4 Rep Power: 8	I have a similar problem. My simulation is diverged around 760CA (intake stroke 526CA - 772CA). I have already set a smoothing function (100 iterations) for temperature and pressure. How can I solve this problem? Increase the iterations of the smoothing function? Best regards