Large Equation Systems may represent a unit in the chemical engineering sense. It makes sense to restrict the accessibility of the variables of such Equation Systems and in a second step add standardized output interfaces to them. In this way, all incoming and outgoing material streams in a model of a process unit could have exactly the same Notation. But it would also be possible to define interfaces that represent control input and output, etc. To provide this kinds of standardized access points, MOSAICmodeling allows the user to specify ports. Two units that have ports can be connected by streams.
Ports belong to an Equation System and cannot exist independently. They have a distinct name and an indication of the Interface they use.
Streams A stream just as a port cannot exist independently from an Equation System. It can combine exactly two ports. It has a distinct identification number, the names of the two ports it connects and an indication to the interface it uses.
The following two tutorials will help you learn how to use ports and streams in MOSAICmodeling; Ports and Streams I – Defining units by adding ports and Ports and Streams II – Using streams to connect ports of units.
In addition, MOSAICmodeling’s ports can be employed to generate custom unit operations for flow sheeting environments. For example, MOSAICmodeling supports an example to the Aspen Custom Modeler to generate unit operations, which can be introduced into any Aspen Plus flowsheet. An example written by Alberto Penteado can be found here also in Ports and Streams III – Export to Aspen Custom Modeler.