Show simple item record

dc.contributor.authorTian, Qingen_US
dc.date.accessioned2014-03-14T20:20:12Z
dc.date.available2014-03-14T20:20:12Z
dc.date.issued2006-11-17en_US
dc.identifier.otheretd-12122006-112751en_US
dc.identifier.urihttp://hdl.handle.net/10919/30062
dc.description.abstractThis dissertation presents the results from an experimental study of three-dimensional turbulent tip gap flow in a linear cascade wind tunnel with 3.3% chord tip clearance with and without moving endwall simulation. Experimental measurements have been completed in Virginia Tech low speed linear cascade wind tunnel. A 24" access laser-Doppler velocimeter (LDV) system was developed to make simultaneous three-velocity-component measurements. The overall size of the probe is 24"à 37"à 24"and measurement spatial resolution is about 100 μm. With 24" optical access distance, the LDV probe allows measurements to be taken from the side of the linear cascade tunnel instead of through the bottom of the tunnel floor. The probe has been tested in a zero-pressure gradient two-dimensional turbulent boundary layer. Experimental measurements (oil flow visualization, pressure measurement, and LDV measurement) for the stationary wall captured the major flow structures of the tip leakage flow in the linear compressor cascade, such as tip leakage vortex, tip leakage vortex separation and tip separation vortex. Large velocity gradients in the tip leakage vortex separation, tip leakage vortex, and tip separation vortex regions generate large production of the Reynolds stresses and turbulent kinetic energy. One of the most interesting features of the tip leakage flow is the bimodal velocity probability histograms of the v component due to the unsteady motion of the flow in the interaction region between the tip leakage vortex and tip leakage jet. The tip separation vortex, tip leakage vortex separation, and tip leakage vortex contain most of turbulent kinetic energy and generate the highest dissipation rate. Relative motion of the endwall significantly affects the tip gap flow structures, especially in the near wall region. Compared to the stationary wall case, velocity gradients in the near wall region for the moving wall case are much smaller and lower velocity gradients in the near wall region cause the low production of Reynolds stresses and turbulent kinetic energy. Similar to the stationary wall case, high Reynolds stresses and turbulent kinetic energy values are mainly located in the vicinity of the tip leakage vortex and tip separation vortex region. The bimodal velocity probability histograms of the v component are also found at the same locations. The tip separation vortex with most of the turbulent kinetic energy generates the highest dissipation rate. The dissipation rate in the tip leakage vortex region is reduced with the decrease of turbulent kinetic energy under the moving wall effect.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartTianDissertation.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectTip Separation Vortexen_US
dc.subjectTurbulenceen_US
dc.subjectCompressoren_US
dc.subjectThree-Dimensional Separationen_US
dc.subjectTip Leakage Vortexen_US
dc.subjectLaser Doppler Velocimeteren_US
dc.subjectTip Gap Flowen_US
dc.subjectOil Flow Visualizationen_US
dc.titleNear Wall Behavior of Vortical Flow around the Tip of an Axial Pump Rotor Bladeen_US
dc.typeDissertationen_US
dc.contributor.departmentAerospace and Ocean Engineeringen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineAerospace and Ocean Engineeringen_US
dc.contributor.committeechairSimpson, Roger L.en_US
dc.contributor.committeememberNeu, Wayne L.en_US
dc.contributor.committeememberTafti, Danesh K.en_US
dc.contributor.committeememberMason, William H.en_US
dc.contributor.committeememberDevenport, William J.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12122006-112751/en_US
dc.date.sdate2006-12-12en_US
dc.date.rdate2007-01-08
dc.date.adate2007-01-08en_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record