Discussion Forum

I have found through a number of trials, that in phase change, that the phase-change transition interval value (deltaT 1->2 or mushy zone) somehow plays too significant of a role. This is the range of temperature over which the material's properties vary gradually from that of the solid to the liquid (see attached png file).

My phase change problem has a eutectic alloy (almost like a pure substance). The solid and liquid material properties are very much the same. So I have no use for this mushy zone feature. But, depending on the size of the model, unless I apply a mushy zone of 10K or above, the solver does not seem to recognize the phase change and gives me a time-temperature plot of constant slope (constant heat input btw).

Though I give the same material properties to both phases, when I apply the mushy zone of 10-15 K, instead of getting a line of zero slope during phase change for the time temperature plot, I am getting a curve of a small slope over that 10-15K range around the melting point. It looks okay, but ideally it should be a straight line of zero slope (no temperature change during melting/solidification).

What am I doing wrong? What have I misunderstood?