Contents STCF 11

Abstract

The existing set of 10 configurations for unsteady flow through vibrating axial-flow turbomachine cascades is extended by the "Standard Configuration 11". This configuration represents a turbine blade geometry with transonic design flow conditions characterized by a normal shock impinging on 75 % real chord on the suction side. Out of a set of test cases covering all relevant flow regimes two cases were selected for publication: A subsonic, attached flow case and an off-design transonic case showing a separation bubble at about 30% real chord on the suction side. The performed tests are shown to be repeatable and suitable for code validations of numerical models predicting flutter in viscous flows. All tests were performed at the annular non-rotating test facility situated at the EPF Lausanne. The present data and geometry are given at midspan, nearly no measurements were made at other blade heights. However, the 3D shape of the blade is prismatic (which means a variable pitch-to-chord ratio over the channel height). The 3D geometry definition can be obtained by stacking the midspan plane profile in radial direction; the tip gap is 0.8mm according to the model drawings. A document available provides detailed information on the 3D geometry and the 3D blade motion as reconstructed from available drawings and reports. The data were published with the permission of ABB, which is gratefully acknowledged.

Standard Configuration 11 is introduced and discussed in a publication presented at the ASME TURBO EXPO 1998, Stockholm, Sweden (paper 98-GT-490), which is published in:

Eleventh standard configuration (Low pressure annular turbine cascade, subsonic and transonic off-design with separated flow)