Type of Document Dissertation Author Lethander, Andrew Tait Author's Email Address Andrew.Lethander@wpafb.af.mil URN etd-12092003-144152 Title Assessment of a Leading Edge Fillet for Decreasing Vane Endwall Temperatures in a Gas Turbine Engine Degree PhD Department Mechanical Engineering Advisory Committee
Advisor Name Title Thole, Karen A. Committee Chair Diller, Thomas E. Committee Member Grossman, Bernard M. Committee Member Ng, Fai Committee Member O'Brien, Walter F. Jr. Committee Member Keywords
- Gas Turbine
- Heat Transfer
Date of Defense 2003-12-01 Availability unrestricted AbstractThe objective of this investigation was to improve the thermal environment for a turbine vane through reduction of passage secondary flows. This was accomplished by modifying the vane/endwall junction to include a leading edge fillet. The problem approach was to integrate optimization methods with computational fluid dynamics to optimize the fillet design. The resulting leading edge fillet was then tested in a large-scale, low speed cascade to verify thermal performance. A combustor simulator located upstream of the cascade was used to generate realistic inlet conditions for the turbine vane. Both computational and experimental results underscore the importance of properly modeling the inlet conditions to the turbine.
Results of the computational optimization process indicate that significant reductions in adiabatic wall temperature can be achieved with a leading edge fillet. While the intent of the initial fillet design was to improve the thermal environment for the vane endwall, computational results also indicate thermal benefit to the vane surfaces. Flow and thermal field results show that a fillet can enhance coolant effectiveness, prevent formation of the leading edge horseshoe vortex, and preclude full development of a passage vortex.
In experimental testing, four cascade inlet conditions were investigated to evaluate the effectiveness of the fillet in reducing endwall temperature levels. Two tested conditions featured a flush combustor/cascade interface, while the remaining two included coolant injection through a backward-facing slot. With the flush interface, fillet thermal performance was evaluated for two inlet total pressure profiles. For the design profile, the fillet had a positive impact on the endwall temperature distribution as well as on the passage thermal field. For the off-design profile, the fillet was observed to have a slightly detrimental impact on the endwall adiabatic temperature distribution; however, passage thermal field results indicate a thermal benefit for the vane suction surface. With the backward-facing slot, thermal tests were conducted for two slot coolant flow rates. For both slot flow rates, the fillet improved endwall thermal protection and prevented coolant lift-off. While increasing the flow rate of slot coolant enhanced endwall effectiveness, fillet thermal performance was similar for the two slot flow rates.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access 01TOC.pdf 338.77 Kb 00:01:34 00:00:48 00:00:42 00:00:21 00:00:01 02CHAPTER1.pdf 280.03 Kb 00:01:17 00:00:40 00:00:35 00:00:17 00:00:01 03CHAPTER2.pdf 827.17 Kb 00:03:49 00:01:58 00:01:43 00:00:51 00:00:04 04CHAPTER3.pdf 687.53 Kb 00:03:10 00:01:38 00:01:25 00:00:42 00:00:03 05CHAPTER4.pdf 1.19 Mb 00:05:31 00:02:50 00:02:29 00:01:14 00:00:06 06CHAPTER5.pdf 14.93 Mb 01:09:06 00:35:32 00:31:05 00:15:32 00:01:19 07CHAPTER6.pdf 10.45 Mb 00:48:22 00:24:52 00:21:45 00:10:52 00:00:55 08CHAPTER7.pdf 89.52 Kb 00:00:24 00:00:12 00:00:11 00:00:05 < 00:00:01 09REFERENCES.pdf 647.26 Kb 00:02:59 00:01:32 00:01:20 00:00:40 00:00:03 10APPENDICES.pdf 552.94 Kb 00:02:33 00:01:18 00:01:09 00:00:34 00:00:02 11VITA.pdf 52.99 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01
If you have questions or technical problems, please Contact DLA.