MICRESS Forum

Dear MICRESS users!

We recently noted an inconsistency in the input of latent heat data for concentration-coupled calculations. Here an input of the enthalpies for all phases is needed, only the differences are evaluated. So you can input either values for the enthalpies if you get them from anywhere (e.g. from the .log-file output in the case of a TC-coupled simulations) or the latent heat by setting the input for the liquid phase to 0 and inputting negative values corresponding to the latent heat for the precipitating phases.
Unfortunately this has been implemented with a wrong sign! So up to now (Okt. 2005) the user should input negative enthalpies or positive values for the latent heat! This not so nice situation will change with all new versions from now.
Specifying latent heat with a wrong sign will most probably lead to a crashing simulation. You can check best by looking at the temperature cange by plotting the .TabL or .TabF ascii temperature output.

We apologize for that!

Bernd

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original message from Bernd

So, finally what should be done?
shall i continue with the negative values..?

Moreover, how can I check with the .TabL output, if after plotting my graph shows variation of temperature which is uneven, i.e., increases at some steps and decreases for some..

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original message from Deep

Dear Deep,

in your version, which is from June 2006, this change already took place! So your negative values are ok. Before, in older versions, people had to put positive values, what was somewhat inconsistent...

In the .TabL output, in column 7, the temperature is written for each tab_log output. So, if you specified a rather small time interval for tab_log outputs (at the end of the output section in the .dri-file) you can examine column 7 either by "naked eye" or by plotting against time (first column), e.g. by using gnuplot or some other plotting software. If you notice fluctuations, you can be pretty sure that the instability described in the solidification board ( see here: http://web.access.rwth-aachen.de/MICRES ... hp?f=9&t=6 ) occured.

Bernd

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original message from Bernd