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Pilot-pilot interaction effects on a prototype DLE gas turbine burner combustion

Kundu, Atanu LU ; Klingmann, Jens LU ; Subash, Arman Ahamed LU and Collin, Robert LU (2016) ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition, GT 2016 In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition 4B-2016.
Abstract

Lean premixed dry low emission (DLE) combustion system in a gas turbine engine is a globally accepted concept to reduce pollutant emissions and to improve combustion efficiency. This study is focused on an industrial downscaled prototype burner (4th Generation Dry Low Emission Burner for SGT-750 designed and manufactured by Siemens Industrial Turbo machinery AB), which has been tested extensively at atmospheric conditions. To enhance the operability and alleviate flame dynamics behavior, multiple fuel and air circuits (i.e. Rich-Pilot-Lean (RPL), Pilot and Main) are engaged in the burner. Primarily, present study evaluates the RPL-Pilot interaction effect on the main combustion zone. A highly swirled flow from the burner exit... (More)

Lean premixed dry low emission (DLE) combustion system in a gas turbine engine is a globally accepted concept to reduce pollutant emissions and to improve combustion efficiency. This study is focused on an industrial downscaled prototype burner (4th Generation Dry Low Emission Burner for SGT-750 designed and manufactured by Siemens Industrial Turbo machinery AB), which has been tested extensively at atmospheric conditions. To enhance the operability and alleviate flame dynamics behavior, multiple fuel and air circuits (i.e. Rich-Pilot-Lean (RPL), Pilot and Main) are engaged in the burner. Primarily, present study evaluates the RPL-Pilot interaction effect on the main combustion zone. A highly swirled flow from the burner exit produces a central recirculation zones (CRZ) to recirculate the hot vitiated gas for sustaining the combustion process. The main flame is stabilized in the inner shear layer (ISL), which is found in the diverging section (named as Quarl). The total power of the burner was varied between 70-140 kW and the fuel used for the experiment was 99.5% pure methane. A short length quartz liner was used for the experiment and the residence time of the combustor is 9 ms. At the liner exit, emission sampling (CO, NOx) has been conducted using a water-cooled emission probe. Optical measurements were permitted, as the Quarl and combustor liner were optically accessible. Planar laser-induced fluorescence of OH molecule (OH-PLIF) and natural chemiluminescence measurements were conducted to visualize the flame characteristics and its response by changing the RPL and Pilot fuel splits. A comprehensive study was performed by varying the RPL residence time to investigate the main flame stabilization and pollutant formation of the burner. Higher RPL residence time exhibits NOx benefits but at the same time flame instability was increased. Pilot fuel percentage modification demonstrate negative impact on NOx formation due to the limited mixing of fuel and air. With the increase of Pilot fuel split, CO emission decreases, which is advantageous for increasing the LBO margin. The study has identified a number of critical situations where the flame was stabilized without any RPL and Pilot combustion. Apart from the experimental results, a simple reactor network model has been applied for predicting NOx emission. Different kinetic mechanisms were assessed and the prediction results are compared to experimental results. Heat loss from the combustor wall played a significant role on emission formation and was included in the reactor model. This study provides a good understanding of the new DLE industrial burner concept and the RPL-pilot interaction effect on the emission.

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organization
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publication status
published
subject
in
ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition
volume
4B-2016
publisher
American Society Of Mechanical Engineers (ASME)
conference name
ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition, GT 2016
external identifiers
  • scopus:84991710659
ISBN
9780791849767
DOI
10.1115/GT2016-57338
language
English
LU publication?
yes
id
63be2b70-2f51-4f9d-8766-f140f537717a
date added to LUP
2016-11-27 10:35:11
date last changed
2017-10-22 05:22:37
@inproceedings{63be2b70-2f51-4f9d-8766-f140f537717a,
  abstract     = {<p>Lean premixed dry low emission (DLE) combustion system in a gas turbine engine is a globally accepted concept to reduce pollutant emissions and to improve combustion efficiency. This study is focused on an industrial downscaled prototype burner (4<sup>th</sup> Generation Dry Low Emission Burner for SGT-750 designed and manufactured by Siemens Industrial Turbo machinery AB), which has been tested extensively at atmospheric conditions. To enhance the operability and alleviate flame dynamics behavior, multiple fuel and air circuits (i.e. Rich-Pilot-Lean (RPL), Pilot and Main) are engaged in the burner. Primarily, present study evaluates the RPL-Pilot interaction effect on the main combustion zone. A highly swirled flow from the burner exit produces a central recirculation zones (CRZ) to recirculate the hot vitiated gas for sustaining the combustion process. The main flame is stabilized in the inner shear layer (ISL), which is found in the diverging section (named as Quarl). The total power of the burner was varied between 70-140 kW and the fuel used for the experiment was 99.5% pure methane. A short length quartz liner was used for the experiment and the residence time of the combustor is 9 ms. At the liner exit, emission sampling (CO, NOx) has been conducted using a water-cooled emission probe. Optical measurements were permitted, as the Quarl and combustor liner were optically accessible. Planar laser-induced fluorescence of OH molecule (OH-PLIF) and natural chemiluminescence measurements were conducted to visualize the flame characteristics and its response by changing the RPL and Pilot fuel splits. A comprehensive study was performed by varying the RPL residence time to investigate the main flame stabilization and pollutant formation of the burner. Higher RPL residence time exhibits NOx benefits but at the same time flame instability was increased. Pilot fuel percentage modification demonstrate negative impact on NOx formation due to the limited mixing of fuel and air. With the increase of Pilot fuel split, CO emission decreases, which is advantageous for increasing the LBO margin. The study has identified a number of critical situations where the flame was stabilized without any RPL and Pilot combustion. Apart from the experimental results, a simple reactor network model has been applied for predicting NOx emission. Different kinetic mechanisms were assessed and the prediction results are compared to experimental results. Heat loss from the combustor wall played a significant role on emission formation and was included in the reactor model. This study provides a good understanding of the new DLE industrial burner concept and the RPL-pilot interaction effect on the emission.</p>},
  author       = {Kundu, Atanu and Klingmann, Jens and Subash, Arman Ahamed and Collin, Robert},
  booktitle    = {ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition},
  isbn         = {9780791849767},
  language     = {eng},
  publisher    = {American Society Of Mechanical Engineers (ASME)},
  title        = {Pilot-pilot interaction effects on a prototype DLE gas turbine burner combustion},
  url          = {http://dx.doi.org/10.1115/GT2016-57338},
  volume       = {4B-2016},
  year         = {2016},
}