This experiment investigated the effects of a non-axisymmetric endwall contour and upstream purge flow on the secondary flow of an inlet guide vane. Three cases were tested in a transonic wind tunnel with an exit Mach number of 0.93-a flat endwall with no upstream purge flow, the same flat endwall with upstream purge flow, and a 3D contoured endwall with upstream purge flow. All cases had a backward-facing step upstream of the vanes. Five-hole probe measurements were taken 0.2, 0.4, and 0.6 Cx downstream of the vane row trailing edge, and were used to calculate loss coefficient, secondary velocity, and secondary kinetic energy. Additionally, surface static pressure measurements were taken to determine the vane loading at 4% spanwise position. Surface oil flow visualizations were performed to analyze the flow qualitatively. No statistically significant differences were found between the three cases in mass averaged downstream measurements. The contoured endwall redistributed losses, rather than making an improvement distinguishable beyond experimental uncertainty. Flow visualization found that the passage vortex penetrated further in the spanwise direction into the passage for the contoured endwall (compared to the flat endwall), and stayed closer to the endwall with a blowing ratio of 1.5 with a flat endwall (compared to no blowing with flat endwall). This was corroborated by the five hole probe results. / Master of Science / This experiment investigated effects of a specially designed endwall (the wall of a jet engine where the vanes end) and adding extra flow upstream through a slot on the inefficiencies of a jet engine vane (a stationary part of the engine that looks like a wing). Three cases were tested in a high-speed wind tunnel at almost the speed of sound-a flat endwall with no extra flow upstream, the same flat endwall with extra flow upstream, and the specially designed endwall with extra flow upstream. All cases had a backward-facing step (a step in the direction as if you are walking downstairs) upstream of the vanes. Measurements of flow direction and pressure were taken at three locations close to the vanes, and were used to calculate parameters relating to efficiency. Additionally, measurements were taken to verify that the vanes functioned correctly. Different colored paints (that do not stick) were used to see how the flow changed between each case. Measurements showed there were no major differences in overall efficiency between the three cases. The specially designed endwall made some areas more efficient, and others less efficient, rather than making the overall vane more efficient. The colored paints showed that a region of spinning flow went further away from the wall with the specially designed endwall. The paints also found that the same region of spinning flow stayed closer to wall when extra flow was added upstream. This was corroborated by the five hole probe results. The results from the paints agreed with the measurements of flow direction and pressure. In conclusion, neither the specially designed endwall or the extra flow made much difference in the overall efficiency (instead, they made some parts more efficient and other parts less efficient).
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/78683 |
| Date | 09 August 2017 |
| Creators | Gillespie, John Lawrie |
| Contributors | Aerospace and Ocean Engineering, Lowe, K. Todd, Ng, Wing Fai, Ma, Lin |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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