Laboratory Studies of the Flow Field Characteristics of Low-Swirl Injectors for Adaptation to Fuel-Flexible Turbines

Cheng, R.K.; Littlejohn, David; Nazeer, Waseem; Smith, K. O.

doi:10.1115/1.2795786

Cited by 63 publications

(29 citation statements)

References 17 publications

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“…One of FutureGen's key components is a cost-competitive hydrogen turbine with ultra low NO x emission and high efficiency. The goal of our research is to adapt our lean premixed low-swirl injector (LSI) [1][2][3][4] to the H 2 turbines.…”

Section: Introductionmentioning

confidence: 99%

Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions

Cheng

Littlejohn

Strakey

et al. 2009

Proceedings of the Combustion Institute

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144

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Laboratory experiments were conducted at gas turbine and atmospheric conditions (0.101 < P 0 < 0.810 MPa, 298 < T 0 < 580K, 18 < U 0 < 60 m/s) to characterize the overall behaviors and emissions of the turbulent premixed flames produced by a low-swirl injector (LSI) for gas turbines. The objective was to investigate the effects of hydrogen on the combustion processes for the adaptation to gas turbines in an IGCC power plant. The experiments at high pressures and temperatures showed that the LSI can operate with 100% H 2 at up to φ = 0.5 and has a slightly higher flashback tolerance than an idealized high-swirl design. With increasing H 2 fuel concentration, the lifted LSI flame begins to shift closer to the exit and eventually attaches to the nozzle rim and assumes a different shape at 100% H 2 . The STP experiments show the same phenomena. The analysis of velocity data from PIV shows that the stabilization mechanism of the LSI remains unchanged up to 60% H 2 . The change in the flame position with increasing H 2 concentration is attributed to the increase in the turbulent flame speed. The NO x emissions show a log linear dependency on the adiabatic flame temperature and the concentrations are similar to those obtained previously in a LSI prototype developed for natural gas. These results show that the LSI exhibits the same overall behaviors at STP and at gas turbine conditions. Such insight will be useful for scaling the LSI to operate at IGCC conditions.

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Section: Introductionmentioning

confidence: 99%

Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions

Cheng

Littlejohn

Strakey

et al. 2009

Proceedings of the Combustion Institute

Self Cite

144

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“…Analyses of the velocity measurements show that the LSI flowfield exhibits self-similarity behavior. Two parameters deduced from the centerline velocity profiles are invoked to characterize self-similar behavior [13,14]. They are the virtual origin of the divergent flow, x 0, and the non-dimensional axial aerodynamic stretch rate, a x .…”

mentioning

confidence: 99%

Effects of Combustor Geometry on the Flowfields and Flame Properties of a Low-Swirl Injector

Cheng

Littlejohn

2008

Volume 3: Combustion, Fuels and Emissions, Parts a and B

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The Low-swirl injector (LSI) is a novel dry-low NOx combustion method that is being developed for gas turbines to burn a variety of gaseous fuels including natural gas, low-Btu fuels, syngases and hydrogen. Its basic principle is described by a top level analytical model that relates the flame position to the flowfield similarity parameters and the turbulent flame speed correlation. The model was based on experimental measurements in open laboratory flames. It has been useful for guiding hardware development. As the LSI is being adapted to different engine configurations, one open question is how the combustor geometry and size affect its basic operating principle. The objective of this paper is to investigate these effects by conducting Particle Image Velocimetry (PIV) measurements in open and enclosed flames produced by a 6.35 cm diameter LSI using two quartz cylinders of 15.5 and 20 cm diameter to simulate the combustor casing. Results from 18 methane-air flames show that the enclosures do not alter the flame properties or the nearfield flow structures. The differences occur mostly in the farfield where the tighter enclosure deters the formation of a weak recirculation zone. The enclosure effects on hydrogen and hydrogen-methane flames were studies using the 20 cm cylinder. The results show that the outer recirculation zone generated at the corner of the dump plane promotes the formation of attached flames. However, the properties and nearfield flow features of the attached flames are similar to those of the lifted flames. At higher stoichiometries, the attached flame collapses to form a compact disc shaped flame that has very different flowfield structures. These results show that the enclosure effects on the LSI are strongly coupled to the fuel type and dump plane geometry but are less dependent on the enclosure size. These observations will provide the basis for developing computational methods that can be used as design tools for LSI adaptation. INTRODUCTIONOur research is motivated by the need of a cost effective, robust, and ultra-low emission combustor for the gas turbines in FutureGen power plant that burns syngases derived from gasification of coal. The objective is to adapt the low-swirl combustion method to these utility size gas turbines that operate on fuels with very high H 2 constituency. Low-swirl combustion is a dry-low-NO x lean premixed combustion method that has been commercialized for industrial heaters. Low-swirl injectors (LSI) have been developed for natural gas industrial turbines (5 -7 MW) in partnership with Solar Turbines of San Diego, California, and for microturbines (100 kW) in partnership with Elliott Energy Systems of Stuart, Florida [1,2].The FutureGen power plant utilizes the Integrated Gasification Combined Cycle (IGCC) approach to produce hydrogen, which is separated from a concentrated CO 2 stream that is then captured for subsequent sequestration. One of its key components is a cost-competitive all-hydrogen fueled turbine with ultra low NO x emission and high eff...

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“…Additionally, the present nozzle configuration is more similar to the jet-LSB than the vane-LSI. The jet-LSB data showed deviations from the linear turbulent flame speed correlation [6]. This may also occur with this nozzle.…”

Section: Characterizing Flow Field Developmentmentioning

confidence: 93%

“…From a practical perspective, many studies have been devoted to the adaptation of the technology to gas turbines. Flow field and emissions characteristics have been reported for various gaseous fuels, including natural gas, hydrogen, and syngas [6][7][8]. Testing of a prototype low-swirl injector for a 7MW gas turbine showed that the absence of heating of the nozzle tip due to the detached flame to be an attribute of this technology in addition to its ultra-low emissions capability [ 9].…”

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confidence: 99%

Technical applicability of low-swirl fuel nozzle for liquid-fueled industrial gas turbine combustor

Koyama

Tachibana

2013

Fuel

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In this study, potentials of the liquid-fueled low-swirl burner technique for industrial gas-turbine combustor application are reported for the first time. A low-swirl fuel nozzle, which is a new implementation of the basic lowswirl burner design, is configured by the velocity measurement of methane-air open flames under atmospheric pressure and a low velocity (~3 m/s) condition. Flow properties, such as the axial stretch rate and virtual origins, are compared with the previously reported values with the axial vane type low-swirl injector, and it is confirmed that the flow field generated from the current implementation is of the typical low-swirl flow. Then, it is shown that the configuration successfully stabilize the lifted flame under much higher velocity (~50m/s) condition with kerosene fuel injected by a typical pressure atomizer. Finally, the fuel nozzle is installed in a 290 kW simple-cycle liquid-fueled gas turbine engine and is found to be operable over the entire operating range. The combustor inlet wall temperatures are shown to be within an acceptable range, even without the cooling air that was required for conventional combustors. This is an advantage of the lifted flame stabilized by the low-swirl technique. Although our focus is not on low emissions characteristics, NOx emissions is also found to be below maximum levels of current Japanese regulations (<84 ppm@15% O2). In sum, the proposed fuel nozzle design shows promise for the application of liquid-fueled industrial gas turbine engines.

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Laboratory Studies of the Flow Field Characteristics of Low-Swirl Injectors for Adaptation to Fuel-Flexible Turbines

Cited by 63 publications

References 17 publications

Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions

Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions

Effects of Combustor Geometry on the Flowfields and Flame Properties of a Low-Swirl Injector

Technical applicability of low-swirl fuel nozzle for liquid-fueled industrial gas turbine combustor

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