Research Papers: Gas Turbines: Combustion, Fuels, and Emissions

Part-Load Operation of a Piloted FLOX® Combustion System

[+] Author and Article Information
Oliver Lammel

e-mail: oliver.lammel@dlr.de

Manfred Aigner

German Aerospace Center (DLR),
Institute of Combustion Technology,
Pfaffenwaldring 38-40
Stuttgart, D-70569Germany

Werner Krebs

Siemens AG, Energy Sector
Fossil Power Generation Division,
Mülheim/Ruhr, D-45473Germany

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the Journal of Engineering for Gas Turbines and Power. Manuscript received August 10, 2012; final manuscript received August 15, 2012; published online February 21, 2013. Editor: Dilip R. Ballal.

J. Eng. Gas Turbines Power 135(3), 031503 (Feb 21, 2013) (9 pages) Paper No: GTP-12-1326; doi: 10.1115/1.4007754 History: Received August 10, 2012; Revised August 15, 2012

A large operational envelope is a key requirement for modern gas turbines. Fuel staging is used here to improve the part load performance of an enhanced FLOX® type combustor. A swirl-stabilized pilot stage is integrated in the FLOX® burner and the results of high pressure lab-scale experiments at system relevant conditions are presented. The operational envelope of the piloted system could be extended by approximately 10%. Pressure scaling and variations of air preheat temperature and jet velocity describe fundamental characteristics of the piloted system. OH* chemiluminescence imaging is used to investigate flame shapes and the effect of the interacting flames. Emissions and pressure pulsations define limits, and optimum operation conditions of the combustor and show the influence of part load relevant parameters.

Copyright © 2013 by ASME
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Fig. 1

Lab-scale test combustor. Schematic and simplified 3D representations of: (a) single-stage (SS) burner configuration, and (b) piloted system (PS), together with the combustion chamber; (c) photo of PS and optically accessible combustion chamber.

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Fig. 2

OH* chemiluminescence imaging. (a) Setup for the ICCD camera and angle of view; (b) and (c) simplified drawings of the PS burner with indication of the visible area of the combustor and nozzles affecting the OH*-CL images.

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Fig. 3

Comparison of (a) NOx (b) CO exhaust gas concentrations for SS and PS (p=1.17×pref, v=vref, T=Tref, PS: λp=λp,ref)

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Fig. 4

Averaged OH*-CL images of SS and PS at λg=λg,ref at similar operation conditions (p=1.17×pref, v=vref, T=Tref, PS: λp=λp,ref) (width of OH*-CL image is reduced here only for comparison)

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Fig. 5

Comparison of (a) PDF and (b) CDF of OH* intensity for the pilot-only (PO), single-stage (SS), and piloted (PS) combustion system

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Fig. 6

Averaged OH*-CL images for pilot-only operation (p=0.67×pref, T=Tref)

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Fig. 7

Averaged OH*-CL images at p=pref for the variation of global lambda with constant pilot lambda λp=λp,ref (T=Tref)

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Fig. 8

Averaged OH*-CL images for a variation of jet velocity (p=pref, λg=λg,ref, T=Tref)

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Fig. 9

NOx exhaust gas concentrations for a variation of (a) combustion chamber pressure (b) jet velocity (λg=λg,ref, λp=λp,ref, and T=Tref)

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Fig. 10

Exhaust gas concentrations (a) NOx, (b) CO for constant pilot lambdas (p=pref, v=vref, T=Tref)

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Fig. 11

Averaged OH*-CL images for a variation of pilot lambda at λg=λg,ref (p=pref, v=vref, and T=Tref)

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Fig. 12

PDF of OH* intensity for a variation of pilot stage lambda at λg=λg,ref (OH*-CL images in Fig. 10)

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Fig. 13

(a) Centroid of flame (CDF=0.5) for a variation of pilot stage lambda at λg=λg,ref (OH*-CL images in Fig. 10); (b) exhaust gas concentrations (left axis) NOx, (right axis) CO for a variation of pilot at λg=λg,ref

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Fig. 14

Pressure amplitude spectra for a variation of pilot lambda at λg=λg,ref (p=pref, v=vref, and T=Tref)

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Fig. 15

Averaged OH*-CL images at preheat temperatures T/Tref=1 and 0.78 (p/pref=1.33, v=vref)

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Fig. 16

Pressure amplitude spectra for a variation of preheat temperature (p/pref=1.33, v=vref, λp=λp,ref)

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Fig. 17

Exhaust gas concentrations (a) NOx, (b) CO for different constant pilot air-fuel ratios (p/pref=1.33, T/Tref=0.78, v=vref)




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