Thermofluid systems by multi-bondgraphs

TLDR: In this paper, a combination of Eulerian and Lagrangian frames of reference is used to determine the convected entropy flows and to further the complete interaction of the variables, as demonstrated by a simple example.

Abstract: Compressible fluid in pipes transports several energy domains, well represented by multi-bondgraphs, where the standard marks, causality, power direction and activation display the structure of the underlying equations. Basic components are resistors from which heat exchangers and thermofluid machines (turbines) follow by extension. They are interconnected by thermofluid multiport accumulators that provide computable causalities. Causalities and equations follow from consideration of the number of degrees of freedom related to the number of state variables; they lead to a combination of Eulerian and Lagrangian frames of reference. Power conservation allows one to determine the convected entropy flows and to further the complete interaction of the variables, as demonstrated by a simple example.