Pump

Figure 1.10: System Pump: acausal bond graph

The acausal bond graph of system Pump is displayed in Figure 5.5 (on page ) and its label file is listed in Section 5.1.6 (on page ). The subsystems are listed in Section 5.1.6 (on page ).

Pump represents an ideal pumping component for compressible or incompressible flow though a pipe, it may also be used as a turbine.

The pump is ideal in the sense that the mass flow rate $\dot m$ depends only on the shaft speed $\omega$:

$$\dot m = k_p \omega$$ (1.3)

It is implemented using three components:

• the ideal isentropic wPipe component which gives the correct energy flows
• the polytropic expansion Poly component which imposes the correct temperature at the output of the pump. This component imposes zero flow at all its ports and therefore does not affect energy balance. It has a bicausal output imposing both the temperature measured by the SS component ``T'' and a zero flow.
• the effort-bicausal transformer EBTF component. This component is an energy-conserving TF component with non-standard causality. The modulus is determined by the two imposed efforts ($T$ and $T_2$), and this modulus determines the flows in the usual way. In particular, it makes sure that the internal energy flowing from the pump to the following components (imposing $T_2$) is correct.