Simulating a 2-Phase Water System: Tips and Resources for Dynamic Simulation

[sandvoxel]

TL;DR Summary

I am trying to dynamically simulate the the internals of a boiler. I have been looking around at different resources but could not find what Im looking for.

I am currently trying to simulate a boiler using the IAPWS-IF97 model of water states. I have looked into the equations but I always seem to run into a condition where I need 2 states at once that depend on one another. I was wondering if anyone had some good learning resources on simulating a 2 phase water system. I have looked at steam tables but would just like some more info about how to simulate it dynamically and not just steady state(even though I am having trouble with that too).

Im a bit new to the thermo world sorry if my question is worded poorly

There is this paper that dose what I want to do but its quite old and it seems to leave out the actual sim of the water and abstracts that away
https://citeseerx.ist.psu.edu/docum...&doi=64e2c22c21e1ab6b2d3f7653121f0c21e07c4fc5

Any help would be greatly appreciated.
Thanks

 

[BvU]

Hello @sandvoxel ,

$\qquad$!​

That's a rather tall order! Thousands of folks have been doing that kind of thing for hundreds of years .
I sympathize that it's not easy to get started, but it is hard to give specific tips for someone you don't know. General advice: start simple, find a few textbooks you like, postpone research papers.
You mention a 323 page PhD thesis; do you want us to read it in order to deal with a rather unspecific comment on dealing with the physical properties?

$\$

 

[Chestermiller]

Let's see your formulation of the problem based on the open system (control volume) version of the first law of thermodynamics. Are you looking at dynamic operation to describe the startup of the boiler, or is the flow rate changing with time? Please provide a sketch of your system so that we can at least see some of the geometry and temperatures. Also, please supply your analysis of the steady state operation using the steam tables.

 

[sandvoxel]

Let's see your formulation of the problem based on the open system (control volume) version of the first law of thermodynamics. Are you looking at dynamic operation to describe the startup of the boiler, or is the flow rate changing with time? Please provide a sketch of your system so that we can at least see some of the geometry and temperatures. Also, please supply your analysis of the steady state operation using the steam tables.

Ok sorry for the long response time but I took some time to do some research and teach myself with some online resources so here is a better description of the problem. The application of the problem is for a game so the load on the system will vary over time as well has the heat input. There will evenly be turbines, pumps generators, and condensers but I want to start with the boiler as it seems to be a sufficiently complex problem to start on before I go into the full cycle. Im hoping to eventually make it modular so I can add things to the loop without having to worry to much about the rest of the system.

A insulated tank with valve open and it has a mass flow rate of 0.001 kg/s. The tank is 150L with a total mass of water of 91.701 Kg and 0.1273 kg of steam at a temperature 150C and a pressure of 0.4761 Mpa. The only mass leaving the system is saturated vapor.

With this problem how would you find the state of the system after 1 second.

I still need to do some more research on my I just don't have enough committed to memory yet to piece together my own equations. Eventually I need to be able to add energy to the system as well as new feed water but i'm simplifying my problem for now to help with understanding.

 

[Chestermiller]

OK. So you have a mixture of saturated liquid water and saturated water vapor in the tank at 150 C. The molar volume of the liquid is 0.001091 m^3/kg and the molar volume of the vapor is 0.393 m^3/kg. Let x be the mass fraction vapor in the tank. Then $$91.701(1-x)(0.001091)+91.701x(0.393)=0.15$$This says that the volume of the tank in terms of the volumes of liquid and vapor is 0.15 m^3. What do you get for x, the mass fraction of vapor? What is the volume of liquid in the tank, and what is the volume of water vapor?