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Thermodynamics and Propulsion

12.6 Velocity Triangles for an Axial Flow Turbine Stage

We can apply the same analysis techniques to a turbine, Figure 12.8. The stator, again does no work. It adds swirl to the flow, converting internal energy into kinetic energy. The turbine rotor then extracts work from the flow by removing the kinetic energy associated with the swirl velocity.

Figure 12.8: Schematic of an axial flow turbine.
Image fig9AxialFlowSchematicTurbine_web

The appropriate velocity triangles are shown in Figure 12.9, where again the axial velocity was assumed to be constant for purposes of illustration. As we did for the compressor, we can write the Euler Turbine Equation in terms of useful design variables:

$\displaystyle 1-\frac{T_{Tc}}{T_{Tb}} = \frac{(\omega r)^2}{c_p T_{Tb}}\left[\f...
...\omega r}\tan\beta_b + \left(\frac{w_c}{\omega r} \tan\beta_c'-1\right)\right].$    

Figure 12.9: Velocity triangles for an axial flow turbine stage.
Image fig9VelTrianglesTurbine_web