The replication of Zwart cavitation model using CEL languages

linlin.geng · October 29, 2017, 16:43

I want to reproduce the mass transfer rate of Zwart cavitation model using the CEL language. the following languages is CEL which were used to replicate the cavitation model of Zwart.

If = if(pabsnc>=3574[kg m^-1 s^-2], pabsnc-3574[kg m^-1 s^-2], 3574[kg m^-1 s^-2]-pabsnc)
Rob = 0.000001[m]
F1 = sqrt((2/3)*(If /Water.density))
Cond = 0.01*3*Vapor.vf*Vapor.densitync*F1 /Rob
Vap = 50*3*0.0005*(1-Vapor.vf)*Vapor.densitync*F1 /Rob
Mass transfer = Vap -Cond

but when i do the solve-process, the computation will diverage quickly. i do not know why. please give me some help. thanks a lot

ghorrocks · October 29, 2017, 18:23

First of all, does the simulation run correctly when you use the built in cavitation model?

If that is OK then do some basic debugging:

Send each of these variables to a user variable, defined to be CEL and set to the value of each of your expressions. Change your output file to write the results file every iteration. I would also add the residuals to the results file as that might have useful information as well.

Then rerun the simulation until it crashes. Look at the results file and check all your variables are the expected values.

October 29, 2017, 16:43	The replication of Zwart cavitation model using CEL languages	#1
linlin.geng New Member linlin.geng Join Date: Oct 2017 Posts: 22 Rep Power: 9	I want to reproduce the mass transfer rate of Zwart cavitation model using the CEL language. the following languages is CEL which were used to replicate the cavitation model of Zwart. If = if(pabsnc>=3574[kg m^-1 s^-2], pabsnc-3574[kg m^-1 s^-2], 3574[kg m^-1 s^-2]-pabsnc) Rob = 0.000001[m] F1 = sqrt((2/3)(If /Water.density)) Cond = 0.013Vapor.vfVapor.densityncF1 /Rob Vap = 5030.0005(1-Vapor.vf)Vapor.densityncF1 /Rob Mass transfer = Vap -Cond but when i do the solve-process, the computation will diverage quickly. i do not know why. please give me some help. thanks a lot

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October 29, 2017, 18:23		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	First of all, does the simulation run correctly when you use the built in cavitation model? If that is OK then do some basic debugging: Send each of these variables to a user variable, defined to be CEL and set to the value of each of your expressions. Change your output file to write the results file every iteration. I would also add the residuals to the results file as that might have useful information as well. Then rerun the simulation until it crashes. Look at the results file and check all your variables are the expected values.