investigation of a prototype industrial gas turbine combustor using ...

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fält. Stabilitetsgränserna och emissionerna undersöktes genom tillförsel av olika mängder luft och bränsle i brännarens enskilda delar. Flammans positionering diagnosticerades med hjälp av laser som skapar ett fluorescerande ljus från molekyler som enbart fanns i flamman. För att mäta strömningsfältet tillsattes partiklar till förbränningsluften. Genom att använda laserljus och ett kamerasystem kunde sedan partiklarnas rörelse dokumenteras. De två laserteknikerna gav möjligheten att visualisera flammas placering och strömningsmönster. Ett ytterligare mål med de lasermätningar som genomfördes var att skapa mätresultat som kan nyttjas för validering av såkallade CFD-beräkningar, avancerade datorbaserade beräkningsmodeller för flöden. iv
Abstract In this thesis, the effect of alternative gaseous fuels, with high hydrogen content and lower calorific value, on gas turbine combustion was investigated experimentally. The aim of the investigation was to find operational limitations for an experimental burner and to supply data for validation of computational fluid dynamics (CFD). Before examination of the actual burner, the laminar flame speed was measured for a range of gases. The measurement technique was based on Schlieren imaging which is a measure of the density gradient through a flame surface. A Bunsen type burner was used to measure the angle of a conical flame from which the laminar flame speed was calculated. In order to improve the comparability of these measurements with other measurement methods the laminar flame speed was corrected for the influence of stretch. The effect of stretch will increase or decrease the flame speed depending on the curvature of the flame and the physical properties of the gases involved in the combustion, e.g. the Lewis number and preferential diffusivity. The gas turbine burner examined was a downscaled version of the burner that is now found in the commercial gas turbine, SGT-750. The burner consists of three concentric sections. The central part is a precombustor called rich-pilot-lean (RPL). The purpose of the RPL is to supply heat and radicals to the other sections to stabilize combustion. The next section is the Pilot, which serves as an intermediate burner in which the equivalence ratio can be optimized to stabilize combustion and minimize NO X emissions. The outermost section is the Main. For the experimental burner approximately 79 % of the mass flow passes through this section. All sections have their own swirlers that create recirculation zones for flame stabilization. The experimental work in this thesis includes measurements of the lean stability limit, emission optimization (primarily NO X ), flame diagnostic through OH-Laser induced fluorescence (LIF) and particle image velocimetry (PIV). Tests were conducted at both atmospheric conditions with preheated air (650 K) and at elevated pressure up to 9 bar. Results from the experimental investigations were also used to validate CFD computations using reduced chemical kinetic schemes, and to validate reactor network calculations based on perfectly stirred reactors (PSR) and plug flow reactors (PFR). v
Page 1 and 2: INVESTIGATION OF A PROTOTYPE INDUST
Page 3: Populärvetenskaplig Sammanfattning
Page 7 and 8: Acknowledgements Without inspiring
Page 9 and 10: List of Papers In this thesis 9 pap
Page 11 and 12: NOMENCLATURE A pre exponential fact
Page 13 and 14: Greek symbols α flame half angle
Page 15: LIF PFR PIV POD PSR RPL SGT SIT SOT
Page 18 and 19: CONTENTS 4.2 OH-Laser Induced Fluor
Page 20 and 21: LIST OF FIGURES 4.3 Schematic energ
Page 23 and 24: CHAPTER 1 Introduction Throughout h
Page 25 and 26: 1.2. Objectives ature zones of the
Page 27 and 28: 1.5. Outline of thesis setup to inv
Page 29 and 30: CHAPTER 2 Gas Turbine Combustor To
Page 31 and 32: Figure 2.2: Temperature entropy dia
Page 33 and 34: 2.1. The combustor Figure 2.3: Ther
Page 35 and 36: 2.1. The combustor Figure 2.5: Cros
Page 37 and 38: 2.1. The combustor Figure 2.7: Illu
Page 39 and 40: CHAPTER 3 Experimental setups The g
Page 41 and 42: 3.2. The atmospheric full burner se
Page 43 and 44: 3.2. The atmospheric full burner se
Page 45 and 46: 3.3. The pressurized central body b
Page 47 and 48: 3.3. The pressurized central body b
Page 49 and 50: 3.4. The pressurized full burner se
Page 51 and 52: CHAPTER 4 Diagnostic methods Severa
Page 53 and 54: 4.1. Particle Image Velocimetry the
Page 55 and 56:
4.2. OH-Laser Induced Fluorescence
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4.3. Schlieren imaging beam between
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CHAPTER 5 Combustor theory - Combus
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5.1. The Borghi diagram The corresp
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5.2. Combustion chemistry Changing
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5.2. Combustion chemistry Figure 5.
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Page 69 and 70:
5.2. Combustion chemistry reactions
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5.3. Chemistry and fluid dynamics c
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5.4. Fluid dynamics in a swirl comb
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CHAPTER 6 Concluding remarks This t
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ecirculation zone for the same sett
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CHAPTER 7 Summary of publications P
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Paper III: Investigation of a Premi
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Paper VI: CFD Investigation of Swir
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Paper IX: Experimental Investigatio
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Appendices 77
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A. Flow visualization using Proper
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Bibliography [1] Genrup, M., and Th
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[17] Syred, N., and Beér, J. M., 1
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[37] Samimy, M., and Lele, S. K., 1
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[58] DARS - Software for Digital An
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like combustor: Experimental result
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