In this screencast I'm going to describe two interactive simulations and the links to these
simulations are given here.
They are located on the Wolfram Demonstration Project Site.
These are ternary phase diagrams, so three components in equilibrium.
And in this case what we are looking at are systems where there are regions of partial
miscibility so we get phase separation.
We have two phases, each phase contains all three components.
We have two phases in equilibrium with each other for a certain region of the phase space.
Now there's another screencast and another interactive simulation for just basic ternary
phase diagrams.
I won't go into details describing ternary phase diagrams but let me give you a little
idea, I'm showing a snapshot of these two simulations and then the pure components are
on the corners.
So for example this corner corresponds to the pure component B and then the side which
is the same color, in this case the side along here, indicates what's the mass fraction of
that particular component.
And you determine that mass fraction by drawing a parallel line to the base opposite the corner.
So you can see this parallel line here, indicating this point here and a mass fraction of about
0.15 of that component.
Likewise for the other components.
And in this two phase region which is shown by an orange line and a purple line.
A point in the two phase region, for example a point here, corresponds to this phase with
this composition and this phase with that composition in equilibrium with each other.
So here I'm showing tie lines connecting phases in equilibrium.
And of course phases in equilibrium means the fugacities of each of the components is
equal.
And then there's a point where the color changes, this is the plat point, on the left is one
phase that's in equilibrium on the right side with a phase of different composition.
So this is a two phase region.
Region outside is one phase.
On the right the phase separation is different and this entire region, so here, is one of
the tie lines connecting this phase in equilibrium with this phase.
So this entire region here is a two phase region we get phase separation.
In the simulations you can select various choices as to what are shown.
On the right you can see grid lines you can see tie lines and then compositions of one
of the phases.
We look at one of the simulations it will be easier to see what's involved.
So let's go to one of the interactive simulations.
So here is one of the interactive simulations.
So I can select this option to better illustrate where we have one phase and where we have
two phases on the diagram.
And then I can select what I want to display.
So I can remove the tie lines to make it less cluttered.
I move the point around so I move the point so it's in the two phase region, or in the
one phase region with the lines now representing what the compositions are.
So I can show grid lines better illustrate this structure.
In this case I can't select these phases because we are in the one phase region.
And in the one phase region you can see the composition is given.
Now if I move the point into the two phase region, it shows just the tie line.
I could show all the tie lines, but let's just look at one.
Now I can select to show the composition of one phase called the beta phase in the purple.
And i can also select to show the composition of the other or I can remove this just so
we can more easily visualize how we get these compositions.
And then moving around to give us a better idea of what phases are in equilibrium.
And then, likewise on the other ternary phase diagram, the same idea is we can move our
mouse to select what is the composition we want to look at and for a given point on the
diagram the composition is displayed.
So hopefully using these interactive simulations will allow you to better understand the behavior.
We have a three component system where there is partial miscibility so we have phase separation.