CAPE-OPEN

Posted: **25 May 2013, 19:20**

In the past, I configured a Property Pack for Air using its constituent gases, then I discovered an entry for Air in the ChemSep1 PCD file.

For that simulation, I created a mixture of four pure components: nitrogen, oxygen, argon, and carbon dioxide, having a mixture molecular weight of 28.9 g/mol. In other words, I made up my own air. While researching this latest question, I noticed in PCDman that air is available in the chemical database. I thought that I looked for air in the past but apparently I missed it. The air that is in the chemical database is a mixture of pure components and may have been set up using the method that you described to add Dowtherm A, which is also a mixture of pure components.

(Q1) Please explain why I cannot add Air, from the PCD file, as a component in a new Property Pack? I cannot save the Property Pack containing Air as a component because errors are detected. (Q2) Why is it in the PCD File?

Posted: **25 May 2013, 20:49**

Q1, in case the error is that no surface tension correlation is available for air, there are several ways to resolve this. You could remove surface tension from your property packages (from the properties tab), or you could change the pure surface tension method to "Compound defined" rather than "Temperature correlation". In this case the selection can be made per compound from the Compounds tab. This defaults to "Temperature correlation" for the compounds for which a temperature correlation is available. For air, a different default will be selected (Brock & Bird).

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Air as a Component

Air as a Component

Re: Air as a Component