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Old   August 8, 2014, 15:36
Default CEL, CP, Pressure
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Mansoor Saleem
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Hello

I am working with porous Domain for Adsobption process by using Zeolite and Water.

For properties of Zeolite I have to use CEL for Cp and Enthalpy H, that CEL is pressure dependent. so when I emter the CEL i get an error that my CP is pressure dependent. Same is the case with Enthalpy.

I need your help in this case.


Thank you so much
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Old   August 9, 2014, 06:57
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Cp is defined as the "specific heat at constant pressure". Hence you cannot have it with varying pressure.

You are going to have to think of a physically realistic method of specifying the properties of this material.
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Old   August 9, 2014, 07:20
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Thank you so much for reply, Ghorrocks

Is there any method to ignore this error, or anyother method to define properties like this.
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Old   August 9, 2014, 07:26
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Sorry, on second thoughts you are right - the Cp can have values at any pressure, but it refers to the specific heat at constant pressure from the specified pressure. So yes, you should be able to define Cp as a function of pressure.

Please post some information about the material properties you are trying to apply, and your attempt at defining them so far.
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Old   August 9, 2014, 07:39
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I just have introduced a big expression for Cp which is a product of different variables and constant values. But because of Pressure its not working.
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Old   August 9, 2014, 10:03
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Ghorrocks

I need help in this regard, can you give me any clue or any tutorial or other method??


Thanks
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Old   August 10, 2014, 06:46
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Please post some information about the material properties you are trying to apply, and your attempt at defining them so far.
Until you do this there is not much I can do. It is up to you to post the information.
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Old   August 11, 2014, 04:45
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Ghorrocks

I am trying to insert, CP, Enthalpy and Density values.only CP and enthalpy are functions of pressure so they are creating problems.
I have only made simple Expressions for that and inserted.
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Old   August 11, 2014, 07:52
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Please post your output file - please include the CEL expressions you are using and the error.
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Old   August 11, 2014, 09:53
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The ANSYS CFX solver warns you if a pressure dependent specific heat capacity is supplied because the equation of state must also be consistent with such specific heat capacity. If such consistency is broken, the setup will be thermodynamically inconsistent

Please read the documentation section about "General Equation of State"

Hope the above helps,
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Old   August 11, 2014, 11:12
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Thank you Ghorrocks and Opaque

I am excluding the pressure factor from CEL because of its negligible effect upon the Cp value. Now my CEL is working

Thank you so much for help and cooperation.
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