The present study is concerned with the unsteady flow field on the blade outer air seal segments of high-work turbines; these segments are installed between the blade tip and outer casing and are usually subjected to extreme heat loads. Time-resolved measurements of the unsteady pressure on the blade outer air seal are made in a low-speed turbine rig. The present measurements indicate the existence of a separation zone on the blade tip which causes a vena contracta to form at the entrance of the tip gap. In addition, a careful comparison between the ensemble-averaged pressure measurement and the corresponding result from steady computation suggests that the pressure on the blade outer air seal can largely be described as being due to a steady flow (in the rotating frame) sweeping past a stationary probe. The ensemble deviation measurement indicates that unsteadiness (from one revolution to the next) is confined to the tip gap.
- International Gas Turbine Institute
Unsteady Effects in Turbine Tip Clearance Flows
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Prasad, A, & Wagner, JH. "Unsteady Effects in Turbine Tip Clearance Flows." Proceedings of the ASME Turbo Expo 2000: Power for Land, Sea, and Air. Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery. Munich, Germany. May 8–11, 2000. V001T03A018. ASME. https://doi.org/10.1115/2000-GT-0444
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