Use this window to enter or over-ride default data for properties that change with temperature, such as density and viscosity, for the vapor, liquid or solid phases of the pure components in your simulation. You may supply tabular data or coefficients of one of a range of equations.
Usage
All the library and user-defined components from the current problem are displayed in the table. Each component has eight push buttons, each one corresponding to a property. To enter data for a property of a component, click on the push button for that component for that property. If components from password protected library are used, user is not allowed to modify the data for such components.
You may enter data for:
Liquid or Solid Vapor Pressure
Vapor, Liquid or Solid Enthalpy
Solid Heat Capacity
Liquid or Solid Density
Vapor or Liquid Viscosity
Vapor, Liquid or Solid Conductivity
Liquid Surface Tension
The Tmin and Tmax listed in the temperature dependent properties are typically set by the lower and higher temperatures in experimental data used to obtain the correlation coefficients. Calculating values with the same equation beyond these limits it is outside the confidence limits of the correlations and may not be accurate. These limits are typical for typical applications and suits the computation within proper accuracy when the process is within those limits.
SimSci has extrapolation techniques for each property, which starts either at the point where there is a function discontinuity (log (1-Tr) for instance will limit T to < Tc) or at the T limits in each equation. The user always has the capability of editing the equations and provide different limits for each component as the need may be. But this may be tedious if there are several dozen components for instance. And the user loses the knowledge of where the true limits are for the given component.
Using the SimSci databank, ideal gas/liquid/solid enthalpies, generally are calculated in range of 200K to 1500K. Above that Cp's are considered constant. This works well for heat calculations, but does not work well for entropy related caluclations such as compressors and expanders. Since most of the ideal gas correlations actually extrapolate well over 1500K or below 200K, the workaround is to simply change maximum/minimum temperature for components present in compressors and expanders, they should operate in that very high/low temperature range.
In order to avoid workaround, two check boxes are provided in PRO/II v10.0.
If “Use extended maximum temperature limits for ideal gas enthalpy, liquid enthalpy and solid enthalpy“ is checked on, then maximum temperature is extended to 5000K or 0.98*Tc for equations using TR (reduced temperature) for all the components
If “Use extended minimum temperature limits for ideal gas enthalpy, liquid enthalpy and solid enthalpy “ is checked on, then for all the components minimum temperature limit will be reset w.r.t their Normal Melting Points’.
See Editing Tabular Data for more information on the entry and editing of tables.
How to get to this window
The Component Properties - Temperature Dependent Properties Window is accessed by pushing the Temperature Dependent button on the PRO/II - Component Properties Window.
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