Tip clearance effects on multistage axial compressor performance and flow structure for small core application

This thesis describes the effect of increasing multistage axial compressor rotor blade tip clearance on embedded stage performance and flow structure for clearance-to-span ratios ranging from 1.4% to 5.6% using steady and unsteady three-dimensional viscous flow multistage computations. Embedded stage efficiency displays decreased sensitivity as rotor tip clearance increases with two flow regimes. For clearance-to-span ratios less than 3.6%, a nearly linear decrease in stage efficiency of 1.6 points per 1% increase in clearance-to-span is identified, in agreement with published literature. For clearance-to-span ratios greater than 3.6%, the computed stage efficiency decreases at a rate of 0.5 points per 1% increase in clearance-to-span. A parameter is developed that correlates with rotor tip section loss generation over a range of rotor tip clearance-to-span ratios and flow coefficients. The blade row relative streamwise tip section blockage increases in both rotor and stator passages and follows trends in rotor and stator tip section loss generation with rotor tip clearance. The tip section velocity deficit into the stator increases with tip clearance resulting in stator suction side corner flow separation, creating a challenge to design a high efficiency stage with larger tip clearance.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2017

Author dc:creator

• Koff, Andrew (Andrew Steven)

Advisor dc:contributor.advisor

• Edward M. Greitzer, Jayant S. Sabnis and Choon S. Tan.

• Aeronautics and Astronautics.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/108933

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/108933