Simulation: Equation system

Mandatory element

After the model has been set up in the “Model” section, the user usually wants to specify the model parameters and initial conditions, initialize iteration variables, and run simulations with the model. This is carried out in the “Simulation” section in the sub-tabs “Equation System” (which will be explained in the following), “Specification”, and “Evaluation”.


The tasks of the tab “Equation System” include loading the equation system that was prepared in the model section and the specification of indices within the model. Once can also take a look at the complete model. Optionally, one can study the included flowsheet in case it has been set up.

Explanation of the editor

Figure 1 shows the editor of the equation system in the “Simulation” tab. Here, you can load your equation system as it has been set up in the “Model” section.

Figure 1: Editor of the equation system in the “Simulation” tab.
FileFilename of your simulation once you have saved or loaded it
DescriptionDescription of your simulation, e.g., its purpose. A description is always necessary
KeywordsOptional keywords for your simulation
UsagesModel elements, i.e., optimizations, in which the s is uimulation sed
EQ SystemFilename of your saved equation system as set up in the “Model” section
Generic SystemProvides generic information on the current equation system
HierarchySub-tab or Generic System. Presents the hierarchy of the loaded equation system, i.e., it shows every sub-system that is part of your equation system
EquationsSub-tab or Generic System. Presents all equations of the currently loaded model
FunctionsSub-tab or Generic System. Presents all functions of the currently loaded model
FlowsheetSub-tab or Generic System. Presents the flowsheet given by the current model (if it has been set up). In this case, it shows you the defined ports as well as internal streams and a visualization.
IndexingDisplays all indices of the current model including their name, their value range, their symbol for the maximum number, their description, and their notation. To instantiate the system, you must assign values to the maximum value of all indices and click on “Confirm Index Data”
Instantiated SystemPresents all equations and functions after all indices have been assigned a maximum number. For example, if your component index is five, you will see five component balances. The instantiated model is helpful when you want to check your model for wrongly formulated equations with respect to the index
Table 1: Elements of the equation system editor in the “Simulation” section.