Surface-Stabilized Fuel Injectors With Sub-Three ppm NOx Emissions for a 5.5 MW Gas Turbine Engine

Author(s):  
Steven J. Greenberg ◽  
Neil K. McDougald ◽  
Christopher K. Weakley ◽  
Robert M. Kendall ◽  
Leonel O. Arellano

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low NOx emission performance. These injectors use a patented technique to form interacting radiant and blue-flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures. A previous ASME paper (IJPGC2002-26088) described the development of this technology from the proof-of-concept stage to prototype testing. In 2002 development of these fuel injectors for the 5.5 MW turbine accelerated. Additional single-injector rig tests were performed which also demonstrated ultra-low emissions of NOX and CO at pressures up to 1.68 MPa (16.6 atm) and inlet temperatures up to 670 °K (750 °F). A pressurized multi injector ‘sector rig’ test was conducted in which two injectors were operated simultaneously in the same geometric configuration as that expected in the engine combustor liner. The multi-injector package was operated with various combinations of fired and unfired injectors, which resulted in low emissions performance and no adverse affects due to injector proximity. To date sub-3 ppm NOx emissions with sub-10 ppm CO emissions have been obtained over an operating range of 0.18 to 1.68 MPa (1.8 to 16.6 atm), inlet temperatures from 340 to 670 °K (186 to 750 °F), and adiabatic flame temperatures from 1740 to 1840 °K (2670 to 2850 °F). A full scale multi-injector engine simulation is scheduled for the beginning of 2003, with engine tests beginning later that year.

2005 ◽  
Vol 127 (2) ◽  
pp. 276-285 ◽  
Author(s):  
Steven J. Greenberg ◽  
Neil K. McDougald ◽  
Christopher K. Weakley ◽  
Robert M. Kendall ◽  
Leonel O. Arellano

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultralow NOx emission performance. These injectors use a patented technique to form interacting radiant and blue-flame zones immediately above a selectively perforated porous metal surface. This allows stable operation at low reaction temperatures. A previous ASME paper (IJPGC2002-26088) described the development of this technology from the proof-of-concept stage to prototype testing. In 2002 development of these fuel injectors for the 5.5 MW turbine accelerated. Additional single-injector rig tests were performed which also demonstrated ultralow emissions of NOx and CO at pressures up to 1.68 MPa (16.6 atm) and inlet temperatures up to 670°K (750°F). A pressurized multi-injector “sector rig” test was conducted in which two injectors were operated simultaneously in the same geometric configuration as that expected in the engine combustor liner. The multi-injector package was operated with various combinations of fired and unfired injectors, which resulted in low emissions performance and no adverse affects due to injector proximity. To date sub-3 ppm NOx emissions with sub-10 ppm CO emissions have been obtained over an operating range of 0.18–1.68 MPa (1.8–16.6 atm), inlet temperatures from 340 to 670K (186–750°F), and adiabatic flame temperatures from 1740 to 1840K (2670–2850°F). A full scale multi-injector engine simulation is scheduled for the beginning of 2003, with engine tests beginning later that year.


Author(s):  
Christopher K. Weakley ◽  
Steven J. Greenberg ◽  
Robert M. Kendall ◽  
Neil K. McDougald ◽  
Leonel O. Arellano

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low NOx emission performance. These injectors use a patented technique to form interacting radiant and blue-flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures. This technology is a successful extension of ALZETA’s line of proven Pyromat™ SB metal fiber burners. A proof-of-concept injector in a full-pressure test rig at NETL in Morgantown, West Virginia achieved sub-3 ppm NOx emissions with concurrent single-digit CO emissions, both corrected to 15% O2. Operating conditions ranged between inlet pressures of 182.4 kPa (1.8 atm) and 1236.2 kPa (12.2 atm), inlet temperatures between 86° C (186° F) and 455° C (850° F) and calculated adiabatic flame temperatures between 1466° C (2670° F) and 1593° C (2900° F). Testing with prototype fuel injectors in test rigs at Solar Turbines last year yielded similar results. In May of 2001, a Solar Saturn 1 MW gas-turbine engine was operated to 95% load with a surface-stabilized injector. Programs are moving forward to adapt these injectors to the Solar Turbines Taurus 60 and Titan 130 engines. Engine tests are scheduled to begin in 2003.


Author(s):  
Steven J. Greenberg ◽  
Neil K. McDougald ◽  
Leonel O. Arellano

ALZETA Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low NOx emission performance. These injectors use a patented technique to form interacting high-flow and low-flow flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures. This technology has been given the product name nanoSTAR™. Previous work involved the development of nanoSTAR technology from the proof-of-concept stage to prototype testing. Rig testing of single injectors and of two injectors simulating a sector of an annular combustion liner have been completed for pressure ratios up to 17 and combustion air inlet temperatures up to 700 K (800°F). This paper presents results from the first ever full-scale demonstration of surface-stabilized fuel injectors. An annular combustion liner, fitted with twelve nanoSTAR injectors was successfully tested up to a pressure ratio of 12 and combustion air inlet temperature of 700 K (800°F). NOx emissions were 2 ppm with CO emissions of 3 ppm both corrected to 15% O2. The combustion system exhibited excellent temperature uniformity around the annular combustor outlet with a maximum pattern factor of 0.16 and engine-appropriate radial profiles.


Author(s):  
Leonel O. Arellano ◽  
Arun K. Bhattacharya ◽  
Kenneth O. Smith ◽  
Steven J. Greenberg ◽  
Neil K. McDougald

Alzeta Corporation has developed surface-stabilized fuel injectors for use in lean-premixed low-emissions combustion systems. These injectors use a patented technique to form interacting high-flow and low-flow flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures conducive for preventing high NOx formation. Solar Turbines and Alzeta had previously worked together to evaluate single-injector and full-scale proof-of-concept test hardware. This paper presents results of a combustion system developed for evaluation on an engine. The next-generation hardware has evolved to include a pilot to handle low engine speeds, and flow circuits have been adjusted to meet low-pressure drop requirements. Screening tests of the full-scale system have been completed at simulated engine conditions in a full-scale rig. Single-digit NOx and CO emissions have been achieved without encountering combustion-driven instabilities. The combustion system demonstrated adequate power turndown with the assistance of the pilot module, and studies to predict the service life of burners have been initiated.


2001 ◽  
Vol 21 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Zhiwu Xie ◽  
Ming Su ◽  
Shilie Weng

Author(s):  
G. J. Sturgess

The paper deals with a small but important part of the overall gas turbine engine combustion system and continues earlier published work on turbulence effects in film cooling to cover the case of film turbulence. Film cooling of the gas turbine combustor liner imposes certain geometric limitations on the coolant injection device. The impact of practical film injection geometry on the cooling is one of increased rates of film decay when compared to the performance from idealized injection geometries at similar injection conditions. It is important to combustor durability and life estimation to be able to predict accurately the performance obtainable from a given practical slot. The coolant film is modeled as three distinct regions, and the effects of injection slot geometry on the development of each region are described in terms of film turbulence intensity and initial circumferential non-uniformity of the injected coolant. The concept of the well-designed slot is introduced and film effectiveness is shown to be dependent on it. Only slots which can be described as well-designed are of interest in practical equipment design. A prediction procedure is provided for well-designed slots which describes growth of the film downstream of the first of the three film regions. Comparisons of predictions with measured data are made for several very different well-designed slots over a relatively wide range of injection conditions, and good agreement is shown.


2018 ◽  
Vol 35 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Mustufa H. Abidi ◽  
Abdulrahman M. Al-Ahmari ◽  
Ali Ahmad ◽  
Saber Darmoul ◽  
Wadea Ameen

AbstractThe design and verification of assembly operations is essential for planning product production operations. Recently, virtual prototyping has witnessed tremendous progress, and has reached a stage where current environments enable rich and multi-modal interaction between designers and models through stereoscopic visuals, surround sound, and haptic feedback. The benefits of building and using Virtual Reality (VR) models in assembly process verification are discussed in this paper. In this paper, we present the virtual assembly (VA) of an aircraft turbine engine. The assembly parts and sequences are explained using a virtual reality design system. The system enables stereoscopic visuals, surround sounds, and ample and intuitive interaction with developed models. A special software architecture is suggested to describe the assembly parts and assembly sequence in VR. A collision detection mechanism is employed that provides visual feedback to check the interference between components. The system is tested for virtual prototype and assembly sequencing of a turbine engine. We show that the developed system is comprehensive in terms of VR feedback mechanisms, which include visual, auditory, tactile, as well as force feedback. The system is shown to be effective and efficient for validating the design of assembly, part design, and operations planning.


1986 ◽  
Vol 108 (2) ◽  
pp. 391-395
Author(s):  
W. J. Dodds ◽  
E. E. Ekstedt

A series of tests was conducted to provide data for the design of premixing-prevaporizing fuel-air mixture preparation systems for aircraft gas turbine engine combustors. Fifteen configurations of four different fuel-air mixture preparation system design concepts were evaluated to determine fuel-air mixture uniformity at the system exit over a range of conditions representative of cruise operation for a modern commercial turbofan engine. Operating conditions, including pressure, temperature, fuel-air ratio, and velocity had no clear effect on mixture uniformity in systems which used low-pressure fuel injectors. However, performance of systems using pressure atomizing fuel nozzles and large-scale mixing devices was shown to be sensitive to operating conditions. Variations in system design variables were also evaluated and correlated. Mixture uniformity improved with increased system length, pressure drop, and number of fuel injection points per unit area. A premixing system compatible with the combustor envelope of a typical combustion system and capable of providing mixture nonuniformity (standard deviation/mean) below 15% over a typical range of cruise operating conditions was demonstrated.


Author(s):  
Jochen R. Kalb ◽  
Thomas Sattelmayer

The technological objective of this work is the development of a lean-premixed burner for natural gas. Sub-ppm NOx emissions can be accomplished by shifting the lean blowout limit (LBO) to slightly lower adiabatic flame temperatures than the LBO of current standard burners. This can be achieved with a novel burner concept utilizing periodic flue gas recirculation: Hot flue gas is admixed to the injected premixed fresh mixture with a mass flow rate of comparable magnitude, in order to achieve self-ignition. The subsequent combustion of the diluted mixture again delivers flue gas. A fraction of the combustion products is then admixed to the next stream of fresh mixture. This process pattern is to be continued in a cyclically closed topology, in order to achieve stable combustion of e.g. natural gas in a temperature regime of very low NOx production. The principal ignition behavior and NOx production characteristics of one sequence of the periodic process was modeled by an idealized adiabatic system with instantaneous admixture of partially or completely burnt flue gas to one stream of fresh reactants. With the CHEMKIN-II package a reactor network consisting of one perfectly stirred reactor (PSR, providing ignition in the first place) and two plug flow reactors (PFR) has been used. The effect of varying burnout and the influence of the fraction of admixed flue gas have been evaluated. The simulations have been conducted with the reaction mechanism of Miller and Bowman and the GRI-Mech 3.0 mechanism. The results show that the high radical content of partially combusted products leads to a massive decrease of the time required for the formation of the radical pool. As a consequence, self-ignition times of 1 ms are achieved even at adiabatic flame temperatures of 1600 K and less, if the flue gas content is about 50%–60% of the reacting flow after mixing is complete. Interestingly, the effect of radicals on ignition is strong, outweighs the temperature deficiency and thus allows stable operation at very low NOx emissions.


Author(s):  
Robert Tacina ◽  
Changlie Wey ◽  
Peter Laing ◽  
Adel Mansour

Results of a low-NOx combustor test with a 15° sector are presented. A multipoint, lean-direct injection concept is used. The configuration tested has 36 fuel injectors and fuel-air mixers in place of a dual annular arrangement of two conventional fuel injectors. An integrated-module approach is used for the construction where chemically etched laminates that are diffusion bonded, combine the fuel injectors, air swirlers and fuel manifold into a single element. Test conditions include inlet temperatures up to 866K, and inlet pressures up to 4825 kPa. The fuel used was Jet A. A correlation is developed relating the NOx emissions to the inlet temperature, inlet pressure, and fuel-air ratio. Using a hypothetical 55:1 pressure-ratio engine, cycle NOx emissions are estimated to be less than 40% of the 1996 ICAO standard.


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