Compressor Work Performance Curves
(Adiabatic, Polytropic, and Shaft Work Curves)
The work performance curve describes the relation between the work performed by the compressor and the actual inlet volumetric flow rate. This curve may be supplied on an adiabatic, polytropic, or shaft basis. At least two sets of values at different flowrates are required for PRO/II.
Fan Laws are applied to modify the work performance curves when the operating speed of the compressor is different from the reference speed. The Fan Law's exponent has a value of 3.0 and cannot be changed.
Usage (Single RPM)
From the Compressor Main Window ...
1. Select the desired work performance curve (adiabatic, polytropic or shaft) and click the Enter Curve button. The Work Performance Curve window will be displayed.
From the Work Performance Curve Window ...
2.Enter values for volumetric flowrate and the corresponding work performed by the compressor in the given table. At least, two pairs of values at different flowrates must be entered. These values cannot be referenced using the Define system.
3. Click OK to accept the entered values or Cancel to cancel the operation. The Compressor Main Window will be displayed.
From the Compressor Main Window ...
4. If the compressor's operating speed is different from the reference speed, enter the values for Reference and Operating Speed parameters.
5. Optionally, you can specify the Maximum Outlet Pressure from the compressor. PRO/II will adjust the work value so that the resulting outlet pressure does not exceed this value.
Usage (Multiple RPM)
From the Compressor Main Window ...
1. Select Multiple Compressor Work Performance Curves to enter data at multiple RPMs and click the Enter Curve button. The Multiple Work Performance Curve window will be displayed.
From Multiple Work Performance Curves Window …
2. Enter a value for RPM, and click the Enter Curve button. The Multiple Work Performance Curve Data window will be displayed.
From Multiple Work Performance Curves Data Window …
3. Enter values for volumetric flowrate and the corresponding work performed by the compressor in the given table. At least, two pairs of values at different flowrates must be entered. These values cannot be referenced using the Define system.
4. Surge and Stonewall Points are optional. The volumetric flowrate and the work corresponding to the number entered here will be considered as these points.
5. Click OK to accept the entered values or Cancel to cancel the operation. The Compressor Main Window will be displayed.
See Editing Tabular Data for additional information on editing operations for the work curve table.
Related Topics
Pressure, Work or Head Specification