The Control of NOx and CO Emissions From 7-MW Gas Turbines With Water Injection as Influenced by Ambient Conditions

Hung, W. S. Y.; Agan, D. D.

doi:10.1115/85-gt-50

Cited by 11 publications

(28 citation statements)

References 1 publication

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“…This principle is illustrated in Figure 1.5 and Figure 1. 6. For a conventional single annular combustor, as more power is required the fuel/ air ratio is increased and thus the flame temperature and NO x production also increase.…”

Section: Staged Combustionmentioning

confidence: 99%

“…These regimes are illustrated schematically in Figure 2.5 and as a function of area ratio or divergence angle and non-dimensional length in Figure 2. 6. Kline et al [1959] described them as follows:…”

Section: Influence Of Geometrical Parametersmentioning

confidence: 99%

“…Combined with a cant angle of 20° this produced an diffuser of overall area ratio 2.36 or 2.6 with a non-dimensional length of about 3. 6.…”

Section: Bled Vortex Controlled and Hybrid Diffusersmentioning

confidence: 99%

“…The flame tube was relatively deep with a depth ratio of 5. 6. They investigated many of the parameters which affect system performance including the losses generated as the flow passes around the flame tube.…”

Section: Flame Tube Depthmentioning

confidence: 99%

“…Using a 48 o sector test rig ( Figure 2.22) Shedden [1993] assessed a datum system performance using a conventional single passage pre-diffuser of area ratio 1.65 and non-dimensional length 4. 6. In addition, Shedden tested two twin-passage pre-diffusers (referred to here as 'Vane' and 'Wedge') both with an overall area ratio of 2.0.…”

Section: High Area Ratio Wide Angle Multi-passage Diffusersmentioning

confidence: 99%

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Experimental and Computational Study of Hybrid Diffusers for Gas Turbine Combustors

Walker

Denman

McGuirk

2003

Volume 2: Turbo Expo 2003

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The increasing radial depth of modern combustors poses a particularly difficult aerodynamic challenge for the prediffuser. Conventional diffuser systems have a finite limit to the diffusion that can be achieved in a given length and it is, therefore, necessary for designers to consider more radical and unconventional diffuser configurations. This paper will report on one such unconventional diffuser; the hybrid diffuser which, under the action of bleed, has been shown to achieve high rates of diffusion in relatively short lengths. However, previous studies have not been conducted under representative conditions and have failed to provide a complete description of the relevant flow mechanisms making optimisation difficult. Utilising an isothermal representation of a modern gas turbine combustor an experimental investigation was undertaken to study the performance of a hybrid diffuser compared to that of a conventional, single passage, dump diffuser system. The hybrid diffuser achieved a 53% increase in area ratio within the same axial length generating a 13% increase in the pre-diffuser static pressure recovery coefficient which, in turn, produced a 25% reduction in the combustor feed annulus total pressure loss coefficient. A computational investigation was also undertaken in order to investigate the governing flow mechanisms. A detailed examination of the flow field, including an analysis of the terms within the momentum equation, demonstrated that the controlling flow mechanisms were not simply a boundary layer bleed but involve a more complex interaction between the accelerating bleed flow and the diffusing mainstream flow. A greater understanding of these mechanisms enabled a more practical design of hybrid diffuser to be developed that not only simplified the geometry but also improved the quality of the bleed air making it more attractive for use in component cooling.

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Section: Staged Combustionmentioning

confidence: 99%

Section: Influence Of Geometrical Parametersmentioning

confidence: 99%

“…Combined with a cant angle of 20° this produced an diffuser of overall area ratio 2.36 or 2.6 with a non-dimensional length of about 3. 6.…”

Section: Bled Vortex Controlled and Hybrid Diffusersmentioning

confidence: 99%

Section: Flame Tube Depthmentioning

confidence: 99%

Section: High Area Ratio Wide Angle Multi-passage Diffusersmentioning

confidence: 99%

See 3 more Smart Citations

Experimental and Computational Study of Hybrid Diffusers for Gas Turbine Combustors

Walker

Denman

McGuirk

2003

Volume 2: Turbo Expo 2003

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The Role of Fuel Preparation in Low-Emission Combustion

Lefebvre

1995

Journal of Engineering for Gas Turbines and Power

178

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The attainment of very low pollutant emissions, in particular oxides of nitrogen (NOx), from gas turbines is not only of considerable environmental concern but has also become an area of increasing competitiveness between the different engine manufacturers. For stationary engines, the attainment of ultralow NOx has become the foremost marketing issue. This paper is devoted primarily to current and emerging technologies in the development of ultralow emissions combustors for application to aircraft and stationary engines. Short descriptions of the basic design features of conventional gas turbine combustors and the methods of fuel injection now in widespread use are followed by a review of fuel spray characteristics and recent developments in the measurement and modeling of these characteristics. The main gas-turbine-generated pollutants and their mechanisms of formation are described, along with related environmental risks and various issues concerning emissions regulations and recently enacted legislation for limiting the pollutant levels emitted by both aircraft and stationary engines. The impacts of these emissions regulations on combustor and engine design are discussed first in relation to conventional combustors and then in the context of variable-geometry and staged combustors. Both these concepts are founded on emissions reduction by control of flame temperature. Basic approaches to the design of “dry” low-NOx and ultralow-NOx combustors are reviewed. At the present time lean, premix, prevaporize combustion appears to be the only technology available for achieving ultralow NOx emissions from practical combustors. This concept is discussed in some detail, along with its inherent problems of autoignition, flashback, and acoustic resonance. Attention is also given to alternative methods of achieving ultralow NOx emissions, notably the rich-burn, quick-quench, lean-burn, and catalytic combustors. These concepts are now being actively developed, despite the formidable problems they present in terms of mixing and durability. The final section reviews the various correlations now being used to predict the exhaust gas concentrations of the main gaseous pollutant emissions from gas turbine engines. Comprehensive numerical methods have not yet completely displaced these semi-empirical correlations but are nevertheless providing useful insight into the interactions of swirling and recirculating flows with fuel sprays, as well as guidance to the combustion engineer during the design and development stages. Throughout the paper emphasis is placed on the important and sometimes pivotal role played by the fuel preparation process in the reduction of pollutant emissions from gas turbines.

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Carbon Monoxide Emissions From Gas Turbines as Influenced by Ambient Temperature and Turbine Load

Hung

1993

Journal of Engineering for Gas Turbines and Power

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The emissions of carbon monoxide (CO) from gas turbines are typically below 100 ppmvd at 15 percent O2 at design full-load operating conditions. The use of water/ steam to reduce NOx emissions from gas turbines results in an increase in CO emissions from gas turbines. This is particularly true when increased rates of water/ steam injection are used to meet stringent NOx limits. Regulations limiting CO emissions from stationary gas turbines were first initiated in the late 1980s by the Federal Republic of Germany and the state of New Jersey in the United States. Since these regulations are silent on ambient and load corrections, these CO limits could be the limiting factor in the current development of dry low-NOx combustion systems by gas turbine manufacturers. In addition, since manufacturers are usually quite specific regarding the conditions for CO guarantees, a conflict for the gas turbine user, who is responsible for the permit application, is readily apparent. This paper attempts to characterize the CO emissions from gas turbines as a function of ambient temperature and turbine load. An ambient temperature correction equation for CO emissions, based on previous work, is presented. The intent is to provide more extensive information on CO emissions such that better defined CO limits can be adopted. Ultimately, this should help the combustion design engineers in developing improved dry low-emissions combustion systems for the gas turbine industry.

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The Control of NOx and CO Emissions From 7-MW Gas Turbines With Water Injection as Influenced by Ambient Conditions

Cited by 11 publications

References 1 publication

Experimental and Computational Study of Hybrid Diffusers for Gas Turbine Combustors

Experimental and Computational Study of Hybrid Diffusers for Gas Turbine Combustors

The Role of Fuel Preparation in Low-Emission Combustion

Carbon Monoxide Emissions From Gas Turbines as Influenced by Ambient Temperature and Turbine Load

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