Function with parameters

foo7 · September 16, 2011, 10:42

Hello guys.

I'm trying to simulate a multicomponent gas flow.
The gas has more than 20 different components, each one with different properties.
The heat capacity of each component follows the following law:

Cp(a,b,c,d,e,T) = a*T +b*(T^2)+c*(T^-1) +d*(e)

Where a,b,c,d and e are parameters which differ from component to component and T is the gas temperature.

I'd like to know if there's a way within CFX for me to write this function Cp(a,b,c,d,e,T) and call it within the materials properties.

This way, when I'm setting each components properties I don't need to write the whole expression, just call the Cp(a,b,c,d,e,T) with the appropriate parameters a,b,c,d and e.

thanks a lot

ghorrocks · September 17, 2011, 08:09

You cannot do CEL functions like this. You can write a fortran subroutine to do it. But I would just write it all out in CEL. Using a text editor it should not be too hard to knock up the CEL expressions for each of the 20 components.

I realise this is not "elegant" and a computer scientist would choke on his weeties, but it should work, is straightforward and will get the job done.

September 16, 2011, 10:42	Function with parameters	#1
foo7 Disabled Join Date: Aug 2011 Posts: 10 Rep Power: 15	Hello guys. I'm trying to simulate a multicomponent gas flow. The gas has more than 20 different components, each one with different properties. The heat capacity of each component follows the following law: Cp(a,b,c,d,e,T) = aT +b(T^2)+c(T^-1) +d(e) Where a,b,c,d and e are parameters which differ from component to component and T is the gas temperature. I'd like to know if there's a way within CFX for me to write this function Cp(a,b,c,d,e,T) and call it within the materials properties. This way, when I'm setting each components properties I don't need to write the whole expression, just call the Cp(a,b,c,d,e,T) with the appropriate parameters a,b,c,d and e. thanks a lot

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September 17, 2011, 08:09		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	You cannot do CEL functions like this. You can write a fortran subroutine to do it. But I would just write it all out in CEL. Using a text editor it should not be too hard to knock up the CEL expressions for each of the 20 components. I realise this is not "elegant" and a computer scientist would choke on his weeties, but it should work, is straightforward and will get the job done.