The influence of periodic unsteadiness, induced by the wakes and vortices from upstream airfoils on the downstream airfoil passage boundary layers and secondary flows, are discussed in this paper. A semi-empirical model is proposed to account for the wake-boundary layer interaction and provide improved estimates of heat loads and losses in the mid-span regions of turbine rotors. Experimental data, obtained from a 1 1/2 stage large scale rotating turbine rig, are presented to highlight the impact of unsteadiness on the characteristics of secondary flows in the downstream rotor and stator passages. Large variations in the size and strength of rotor secondary flow vortices are observed as rotor passages sweep through the flow distortions generated by upstream stator airfoils. The rotor secondary flow vortices persist through the second stator and have a pronounced effect on both the spanwise distribution of gas angles and airfoil heat loads in the second stator. In particular, these upstream rotor-generated vortices cause underturning of flow in the endwall regions and overturning of flow in the mid-span region of the second stator.
Rotor-stator interaction in multi-stage axial-flow turbines
Rotor-Stator-Wechselwirkung in mehrstufigen Gasturbinen mit Axialstroemung
AIAA-Papers ; Jul ; 1-16
1988
16 Seiten, 13 Bilder, 1 Tabelle, 46 Quellen
Aufsatz (Konferenz)
Englisch
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