[Q] CHEMISTRY POST PROCESSING takes a long time...

Whitebear · August 5, 2014, 20:24

Does anyone have an experience that chemistry post processing takes a long time? I am solving coal combustion problem and pre processing solver takes one day but more than two days has taken for solver solves NOx calculation. How can I reduce the chemistry post processing time? I set 8 rays in radiation, upwind for advection scheme and 12 cores(hyper threading) parallel calculation for 1.2million nodes.

ghorrocks · August 6, 2014, 08:21

I presume you mean the solver time is long - the pre- and post processing should be quick regardless of whether chemistry is present.

Yes, chemistry can make the equations less numerically stable and that leads to longer run times. "CFD" and "I need a more powerful computer" are often said together.

Opaque · August 6, 2014, 09:22

Not sure what is the source of your problem; however, you should not run ANSYS CFX with hyperthreading on. Performance will suffer once you start running in parallel.

Whitebear · August 8, 2014, 09:39

Thank you very much indeed ghorrocks and Opaque.

August 5, 2014, 20:24	[Q] CHEMISTRY POST PROCESSING takes a long time...	#1
Whitebear Member Jinwhan Ryuk Join Date: Feb 2013 Location: South Korea Posts: 91 Rep Power: 13	Does anyone have an experience that chemistry post processing takes a long time? I am solving coal combustion problem and pre processing solver takes one day but more than two days has taken for solver solves NOx calculation. How can I reduce the chemistry post processing time? I set 8 rays in radiation, upwind for advection scheme and 12 cores(hyper threading) parallel calculation for 1.2million nodes.

August 8, 2014, 09:39	Thank you.	#4
Whitebear Member Jinwhan Ryuk Join Date: Feb 2013 Location: South Korea Posts: 91 Rep Power: 13	Thank you very much indeed ghorrocks and Opaque.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
pimpleFoam: turbulence->correct(); is not executed when using residualControl	hfs	OpenFOAM Running, Solving & CFD	3	October 29, 2013 08:35
AMI interDyMFoam for mixer nu problem	danny123	OpenFOAM Programming & Development	8	September 6, 2013 02:34
How to write k and epsilon before the abnormal end	xiuying	OpenFOAM Running, Solving & CFD	8	August 27, 2013 15:33
mixerVesselAMI2D's mass is not balancing	sharonyue	OpenFOAM Running, Solving & CFD	6	June 10, 2013 09:34
same geometry,structured and unstructured mesh,different behaviour.	sharonyue	OpenFOAM Running, Solving & CFD	13	January 2, 2013 22:40

August 6, 2014, 08:21		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	I presume you mean the solver time is long - the pre- and post processing should be quick regardless of whether chemistry is present. Yes, chemistry can make the equations less numerically stable and that leads to longer run times. "CFD" and "I need a more powerful computer" are often said together.

August 6, 2014, 09:22		#3
Opaque Senior Member Join Date: Jun 2009 Posts: 1,804 Rep Power: 32	Not sure what is the source of your problem; however, you should not run ANSYS CFX with hyperthreading on. Performance will suffer once you start running in parallel.