Stream Connectors - An Extension of Modelica for Device-Oriented Modeling of Convective Transport Phenomena

Abstract

Modelica 3.0 as well as other physical modeling languages have two basic variable types to describe the interaction of physical components: “Potential” (or across) variable and “flow” (or through) variable. It is shown that with these variable types it is not possible to describe in a numerically sound way bidirectional flow of matter. Other alternatives based on signal flow oriented modeling have severe restrictions how components can be connected together. This fundamental problem is addressed in Modelica 3.1 by introducing a third type of connector variable for physical systems, called stream variable, declared with the prefix stream. This article motivates and introduces stream variables. Examples are given for their utilization in basic fluid models.