Click the free power turbine option for a free power turbine not driving a compressor. If a free power turbine also has the Free state rotor speed option set, the model should be used for transient calculation only to simulate free power turbine accels and decels with a power turbine speed governor. Use user specified rotor speed for steady state calculations with free power turbine to prevent GSP from searching a steady state power turbine speed / load combination which often does not exist (power turbine either stops or overspeeds).
For off-design performance a component map is used. The map file consists of tables with corrected mass flow, efficiency and pressure ratio as a function of corrected normalized rotational speed and beta. The map operating point corresponding to the design operating point is specified using the map design rotational speed and beta values. Click the Graph button in the Map tab sheet to view the map graphically and note the yellow rectangle which can be used to change the map design point. In the map graph also the beta-lines can be show after activating the appropriate item in the Options menu.
For both the compressor drive and free power drive option, (extra) power may be absorbed from the shaft using the PTO power and Torque specification fields. In this case it is also possible to use the Power Turbine Load Control component.
Free power turbine
