INVESTIGATION OF PASSAGE FLOW FEATURES IN A TRANSONIC COMPRESSOR ROTOR WITH CASING TREATMENTS
Müller, Martin W. and Schiffer, H.-P. and Voges, Melanie and Hah, Chunill (2011) INVESTIGATION OF PASSAGE FLOW FEATURES IN A TRANSONIC COMPRESSOR ROTOR WITH CASING TREATMENTS. In: Proceedings of ASME Turbo Expo 2011. ASME Turbo Expo 2011: Power for Land, Sea and Air, 6.-10. Juni 2011, Vancouver, Canada.
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An experimental investigation on casing treatments in a one-stage transonic compressor is presented. The reference case consists of a radially staggered blisk and six circumferential grooves. Speedlines show that this axisymmetric treatment already provided a substantial increase in operating range with relatively small losses in efficiency. Since the onset of rotating stall in tip-critical high-speed compressors is always linked to the tip-leakage flow and the built-up of blockage within the blade passage, high-resolution measurement techniques have been employed to investigate the corresponding effects. Results with Particle Image Velocimetry show that the interaction between the tip leakage vortex and the shock front cause a blockage area. When throttled further, the blockage increases. The shock structure changes similar to the phenomena of vortex breakdown described by different researchers in the past, but a stagnation point is not present. Before reaching the stability limit, the interface line between the incoming flow and the blocked area moves towards the inlet plane of the rotor indicating spike-type stall inception. Wall pressure measurements confirmed this theory for the smooth wall, but with circumferential grooves applied, a part span stall cell develops prior to the stability limit. In order to assess the performance of circumferential grooves, two additional configurations are presented. The corresponding measurements addressed the questions whether circumferential grooves also provide an operating range extension when applied to an optimized rotor design with higher initial stall margin. Therefore, an identical casing treatment is applied to a forward swept rotor. The second question is, how circumferential grooves perform in direct comparison to a non-axisymmetric endwall structure. Axial slots have been applied to the radially staggered rotor. While the stall margin exceeds all other configurations, detrimential effects in efficiency are observed. A detailed anaylsis of probe data shows the changes of the radial profile at the rotor outlet which allows recommendations for more efficient CT designs. Parameters allowing to evaluate the CT influence are presented.
|Document Type:||Conference or Workshop Item (Speech, Paper)|
|Title:||INVESTIGATION OF PASSAGE FLOW FEATURES IN A TRANSONIC COMPRESSOR ROTOR WITH CASING TREATMENTS|
|Journal or Publication Title:||Proceedings of ASME Turbo Expo 2011|
|In ISI Web of Science:||No|
|Keywords:||compressor, casing treatment, tip leakage flow, wall pressure, PIV, shock|
|Event Title:||ASME Turbo Expo 2011: Power for Land, Sea and Air|
|Event Location:||Vancouver, Canada|
|Event Type:||international Conference|
|Event Dates:||6.-10. Juni 2011|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Aeronautics|
|HGF - Program Themes:||L ER - Engine Research|
|DLR - Research area:||Aeronautics|
|DLR - Program:||L ER - Engine Research|
|DLR - Research theme (Project):||L - Virtual Engine and Validation Methods|
|Institutes and Institutions:||Institute of Propulsion Technology > Engine Measurement Systems|
|Deposited By:||Melanie Voges|
|Deposited On:||19 Jan 2012 11:08|
|Last Modified:||19 Jan 2012 11:08|
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