Jet Impingement and shower head cooling are critical cooling techniques used to maintain turbine blades at operational temperatures. Jet impingement is extremely effective at removing large amounts of heat flux from the target surface, the inner blade wall, through stagnation point heat transfer. Shower head cooling produces a cooling film around the exterior of the blade, in return reducing external heat flux. The current work consisted of investigating the jet impingement effectiveness with rotational effects for two different cooling schemes. The analysis was conducted numerically using STAR CCM+ with two different turbulence models, the three equation Lag Elliptic Blending K Epsilon model and the seven equation Elliptic Blending Reynolds Stress Transport (EB RST) model. The EB RST model incorporated the Generalized Gradient Diffusion method. The blade used was NASA/General Electrics E^3 row 1 blade. Two conjugate heat transfer models were developed for just the leading-edge portion of the blade, one with and one without shower head holes. The models consisted of a quarter of the blade-span to reduce computational expense and only one jet was analyzed. A flow field analysis was performed on the free jet region to analyze the potential core velocity and turbulent kinetic energy profiles. Nusselt Number spanwise distribution and external blade temperature profiles were also evaluated. The investigation showed, for both turbulence models, that rotational effects produce turbulent kinetic energy within the jet's potential core, reducing the incoming jet velocity and hence reducing impingement effectiveness. While both turbulence models illustrated an increase in turbulent kinetic energy throughout the structure of the impinging jet, the magnitudes and locations varied significantly. This is due to the well-known underprediction of turbulent dissipation in the K-Epsilon family of turbulence models, as well as the location of applications of the vorticity tensor to the transport equations.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-1110 |
| Date | 01 January 2020 |
| Creators | Olson, Weston |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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