To calculate the overall device efficiency requires that you specify both an inlet and outlet boundary condition corresponding to points 1 and 2 on the T-s diagrams shown in Figure 1.2: T-s Diagrams for Compression and Expansion Processes. Only single boundary condition regions of type inlet and outlet are currently supported. The inlet entropy and total enthalpy are based on mass flow average values. The monitored efficiency values are based on mass average field efficiency at the selected outlet boundary condition.

For single phase cases or multiphase cases running the homogeneous model, the following variables are written to the CFX-Solver Output file:

For multiphase cases running the homogeneous mass and momentum model, but inhomogeneous energy equations (such as condensing/evaporation disperse droplets, disperse solids):

Compression and expansion efficiencies are calculated only for the continuous phase; all other dispersed phases are ignored.

For multiphase cases running the inhomogeneous mass and momentum model and inhomogeneous energy equations:

For each continuous phase, compression and expansion efficiencies are calculated.

All of the output variables are either Total to Total or Total to Static depending on which mode you have selected in CFX-Pre.

When efficiency monitoring is activated field efficiencies are also written to the final results file, Standard backup and transient results files, and Selected Variables transient files where required. When efficiency monitoring is activated, the field variables can be used in CEL expressions, monitor points (callback and point monitors), and User Fortran.

In addition to the global efficiency fields, described in the previous section, the following field variables are written to results and backup files during a simulation:

For single phase or multiphase homogeneous mass and momentum with homogeneous energy equation model:

For homogeneous mass and momentum with inhomogeneous energy equation:

For inhomogeneous mass and momentum with inhomogeneous energy equation:

All of the output variables are either Total to Total or Total to Static depending on which mode you have selected in CFX-Pre.