• Every fluid network contains its own pre-defined set of fluid types (O2, N2, etc).
  • Once this is defined, a network ONLY has those fluids in it and cannot consider other fluid types.
  • Higher # of fluid types slows the network down. Though it’s not as bad as # nodes, we still try to minimize the fluid types.
  • Networks that must flow between each other should use the same set of types that need to be transferred, otherwise types have to be converted to other types. More on that in section 6.
  • It’s a hassle to add or remove fluid types later, so it’s a good idea to figure it out before you start drawing.
  • So, do a design pass over your entire project and sort out which fluids are in which networks before you start drawing any of them.

• A network can have both gas & liquid phase types (e.g. GUNNS_H2O & GUNNS_WATER).

• “Air” networks:
  • Typically include these 4, as they make up ~ 99% of air: GUNNS_N2, GUNNS_O2, GUNNS_H2O, GUNNS_CO2
  • TS-21 also adds GUNNS_CH4 & GUNNS_H2.
  • Others can be added if needed, mainly depending on whether any models need to interact with them. In trace amounts, consider using Trace Compounds instead.
  • N2 is the most inert gas in air and also has the highest portion, so we typically consider all other trace gasses as just more N2 as a simplification.
    • Argon, CO, etc.

• What if the fluid type you want isn’t in the list?
  • The best you can do is approximate it with another fluid type. Pick something with similar values for the properties you care about: molecular weight, PVT, Cp, etc.
  • Let us know if you need a new fluid type. If fluid properties data is readily available, we can add it in about a day.

Let’s review the procedure for starting a new network drawing:

• Open the Empty Network template drawing in gunns/draw/drawings/EmptyNetwork.xml
• Rename the network container
• Save the file as your own drawing in your user model area
• Ready to go!

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