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Numerical and Experimental Investigation of Swirl and Preheat Effects in a Double-Swirl Gas Turbine Model Combustor

Asadi, Benyamin | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51380 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Mardani, Amir
  7. Abstract:
  8. High swirl combustors with circulative structures in the flow field, have a highly flame stability with a wide range of operating conditions. In this study, Sharif Gas Turbine Model Combustor (SGTMC) which is a double high swirl burner, was investigated experimentally and numerically. In experimental studies, SGTMC with different settings of swirlers is investigated in terms of flame lean blow-out(LBO), wall temperature, the exhaust gas composition and pollutant and also flame geometry parameters. Setting of burner are changed by variations in air fraction between inner and outer air inlets or swirlers’ vanes degrees and flow rotation directions. The results indicate that the concentrations of NOX and CH4 were below 20 ppm in most cases which is sign of appropriate characteristics of this burner. The burner lean blow-out boarders also indicate better performance of combustor under confinement condition in comparison without un-confinement one up to 87 percent. In addition, the air inlet preheating improved the LBO margin up to 9 percent. Furthermore, another phenomenon which observed during experimental studies is flame’s adhesion to the head of burner. According the onsite observation of operating burner, the weakening of jet’s momentum and combustion are the reasons of flame’s adhesion to the head of burner. During experimental studies, a favorable burner swirlers configuration is concluded without flame’s adhesion under different operating condition. In numerical studies, GTMC is modeled in a 3D approach by Reynolds stress (RSM) turbulence model, EDC combustion model, DRM-22 chemical mechanism, and using URANS method under hot and cold condition. Predictions are compared with the measurements and shows a reasonable agreement with the measurements. The predictions indicate the existence of an unsteady phenomenon famed to Processing Vortex Core (PVC). Frequency of PVC is around 1563 Hz under in clod flow which increase to 1823 Hz, by combustion. Results show that PVC could be a reason of proper mixing of fuel and air inside the combustion chamber
  9. Keywords:
  10. Preheating ; Pollutant ; Swirl Burner ; Flame Stability Criteria ; Gas Turbine Model Combuster (GTMC) ; Processing Vortex Core (PVC)

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