I am modeling a closed natural circulation loop, filled with water. Some parts of the loop are heated, some are cooled and other are assumed adiabatic. As an effect of heating and cooling the density of water changes and so does the total pressure in the loop. My question is as follows:
Is there a way to calculate the total pressure of the system in terms of, for example, mean density, mean temperature and total volume of the system? For air, the ideal gas equation should be a nice approximation, but it is not applicable for liquids. The problem becomes more complex when the water starts to boil at some point, then it is a two-phase fluid.
I have seen answer to this question What equation of state is needed for liquid states? but it does not help in my case.