Equation forms for temperature-dependent properties in AVEVA Thermodynamic Data Manager

When you create a custom library in AVEVA Thermodynamic Data Manager (TDM), you may want to adjust the temperature-dependent property data for the components in your unary data banks.

Changes to the unary data bank affect all Fluids in all AVEVA Process Simulation simulations that use the corresponding custom library. If you want to make simulation-specific changes to the temperature-dependent property data without affecting other simulations, you should use the thermodynamic data overrides available in the Fluid Editor in AVEVA Process Simulation instead of modifying the unary data bank in AVEVA Thermodynamic Data Manager.

In AVEVA Process Simulation, you can find the temperature-dependent properties on the Temperature Dependent tab in the Component Data section of the Fluid Editor. See Overrides for component property data for more information.

In TDM, you can find the temperature-dependent properties on the TempDep tab when you select the component that you want to modify. There are a number of different equation forms (correlations) that you can choose from when you input your data. You should choose the equation form that best fits the temperature-dependent data that you have on hand for the component. The TempDep tab shows the equation form for only one temperature-dependent property at a time. Use the controls in the Properties area to choose the temperature-dependent property that you want to view or modify the equation form for.

To provide more intuitive thermodynamic specifications, AVEVA Process Simulation shows correlations and coefficients for specific heat capacity instead of enthalpy. However, TDM shows only the correlations and coefficients for enthalpy, and the specific heat capacity does not appear on the TempDep tab. If you want to view or change the correlation coefficients for the specific heat capacity, you must use the Temperature Dependent tab in the Component Data section of the Fluid Editor. You should use the derivative forms of the correlations to specify the coefficients for specific heat capacity. See the documentation for the corresponding correlation for more information on the mapping between the integrated (enthalpy) and derivative (specific heat capacity) forms of the correlation.

The following table lists the available equation forms that you can use for each temperature-dependent property. The values in the Correlations column correspond to the value that you can select in the Correlation No. list on the TempDep tab in TDM or in the Correlation column on the Temperature Dependent tab in AVEVA Process Simulation.

1 Specific heat capacity correlations are available only in the Fluid Editor in AVEVA Process Simulation. If you want to view or change the correlation coefficients for the specific heat capacity, you must use the Temperature Dependent tab in the Component Data section of the Fluid Editor. You should use the derivative forms of the correlations if you are specifying coefficients for specific heat capacity. See the documentation for the corresponding correlation for more information on the mapping between the integrated (enthalpy) and derivative (specific heat capacity) forms of the correlation.

2 For ions, we do not calculate the liquid specific heat capacity. Instead, the calculated property is the partial molar heat capacity at infinite dilution.

3 Correlation 91 currently applies only to the saturated liquid density for ionic species. Therefore, it does not appear in the Correlation No. list for any other temperature-dependent property.

4 While the dielectric constant is a temperature-dependent property, it does not appear on the TempDep tab in TDM. However, you can view and update the correlation coefficients in the Fluid Editor in AVEVA Process Simulation. You can find these correlation coefficients in the Component Data section of the Fluid Editor, on the Temperature Dependent tab.

5 Correlation 55 currently applies only to the dielectric constant. Therefore, it does not appear in the Correlation No. list for any other temperature-dependent property.