countours for a composition triangle in a multicomponent system
This application is used for the calculation of
on a triangular composition grid in a multicomponent system.
The application is number 29.
user_v(application_code) = 29 !
Before initiating the calculations it is necessary
to define a
datafile for the system to be covered by the calculations, to classify
any phases required to be absent or identified as
giving rise to miscibility gaps and to specify the pressure. All this
can be set up using the normal APPLICATION commands within MTDATA.
Firstly it is necessary to specify the number of
steps in composition
forming a grid on the triangular cut.
A value of 20 might be appropriate although this can be adjusted for
coarser or finer calculations.
user_v(number_of_steps) = 20 !
and the temperature and pressure:
press 101325 temp 1273.15 !
The application is
a multicomponent system (ie with at least three components). The
following example, however, is for a three component system. To
calculate sections in higher order systems it is necessary simply
to add more components to the composition groups.
'A' 0.9998 0.0001 0.0001 !
'B' 0.0001 0.9998 0.0001 !
'C' 0.0001 0.0001 0.9998 !
The corners of the diagram should be assigned to
user_v(group_lower_left) 'A' !
user_v(group_top) 'B' !
user_v(group_lower_right) 'C' !
Finally it is necessary to define the limits and
the step interval for countouring the enthalpies. This
is done by setting the appropriate user variables.
user_v(contour_start) -20000 !
user_v(contour_end) +16000 !
user_v(contour_step) 2500 !
The results of the calculations are stored in a
".liq" file for subsequent replotting perhaps using
the LIQSURF application
which provides a three dimension perspective on the calculations.