Multiphase Flow Properties varying with temperature!

starlight · April 28, 2016, 08:42

Hello everyone and thank you in advance for your help!

I have to simulate an internal multiphase flow with properties like density, dynamic viscosity, etc. varying with temperature.
So far it has been performed an isothermal simulation.
I would like to understand which is the best model setup and how to set/manipulate for example the polynomial density.
Unfortunately I'm not an expert and this post may be really confusing, sorry about that.
Anyone could help?! Star CCM+ manual is no longer helping me.

marmot · May 9, 2016, 17:12

I like to use the User Defined EOS, I create a table, simple csv file and import that below in tools, csv file looks like this T (K), rho (kg/m**3), mu (Pa-s), k (W/m2-K)

now for example density, select method Table(T)
set T and rho

I find working with tables easier than coming up with field functions or polynomials, its not slower in terms of CPU time

starlight · May 10, 2016, 11:58

Thank you very much for your reply! I'm trying working with user-defined EOS but I'm having some issues with calculation convergence!

marmot · May 11, 2016, 06:24

You might need to limit the min and max Temperature in the reference conditions. Than make sure your temperature dependent tables cover the temperature range you limit.

You might want to do things like gas phase is constant density, liquid phase is temperature dependent, does it converge, than try both.

Make sure your temp data is smooth, no large jumps and such

remember multiphase convergence is an art form, have fun

April 28, 2016, 08:42	Multiphase Flow Properties varying with temperature!	#1
starlight New Member Francesca Guardavaccaro Join Date: Feb 2015 Posts: 9 Rep Power: 11	Hello everyone and thank you in advance for your help! I have to simulate an internal multiphase flow with properties like density, dynamic viscosity, etc. varying with temperature. So far it has been performed an isothermal simulation. I would like to understand which is the best model setup and how to set/manipulate for example the polynomial density. Unfortunately I'm not an expert and this post may be really confusing, sorry about that. Anyone could help?! Star CCM+ manual is no longer helping me. Last edited by starlight; April 28, 2016 at 10:05.

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May 9, 2016, 17:12		#2
marmot Senior Member kevin alun Join Date: Sep 2011 Location: Germany Posts: 106 Rep Power: 15	I like to use the User Defined EOS, I create a table, simple csv file and import that below in tools, csv file looks like this T (K), rho (kg/m**3), mu (Pa-s), k (W/m2-K) now for example density, select method Table(T) set T and rho I find working with tables easier than coming up with field functions or polynomials, its not slower in terms of CPU time

May 10, 2016, 11:58		#3
starlight New Member Francesca Guardavaccaro Join Date: Feb 2015 Posts: 9 Rep Power: 11	Thank you very much for your reply! I'm trying working with user-defined EOS but I'm having some issues with calculation convergence!

May 11, 2016, 06:24		#4
marmot Senior Member kevin alun Join Date: Sep 2011 Location: Germany Posts: 106 Rep Power: 15	You might need to limit the min and max Temperature in the reference conditions. Than make sure your temperature dependent tables cover the temperature range you limit. You might want to do things like gas phase is constant density, liquid phase is temperature dependent, does it converge, than try both. Make sure your temp data is smooth, no large jumps and such remember multiphase convergence is an art form, have fun