The acausal bond graph of system wPipe is displayed in Figure 1.14 (on page ) and its label file is listed in Section 1.1.15 (on page ). The subsystems are listed in Section 1.1.15 (on page ).
wPipe represents an ideal (energy conserving) pipe carrying a fluid with work transfer. To ensure energy conservation, power bonds are used and connected by (energy conserving) TF components.
The central 1 junction carries mass flow () and the four ports are connected to this by appropriate transformers. In the case of the hydraulic ports, these transformers are modulated by the corresponding fluid density. The bonds impinging on this 1 junction carry the corresponding effort variables; in particular, the thermal bonds carry specific internal energy and the hydraulic bonds carry where is the pressure and the specific volume.
The ports ``Work_in'' and ``Work_out'' are convenient for attaching (for example) the shadt work of a pump, turbine or compressor.
The ports are