The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Ziqu Ouyang - One of the best experts on this subject based on the ideXlab platform.
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the influence of air stage method on flameless combustion of coal gasification fly ash with coal self preheating technology
Fuel, 2019Co-Authors: Ziqu Ouyang, Yongjie NaAbstract:Abstract As the by-product of circulating fluidized bed (CFB) coal gasification, coal gasification fly ash (CGFA) contains low volatile matter (lower than 6 wt%) and high ash matter (higher than 40 wt%), which cannot be burnt steadily and effectively with conventional combustion technologies. However, the annual output of CGFA is enormous in China and the available energy is considerable. Therefore it is necessary to achieve a highly efficient and clean combustion of CGFA. As a novel combustion technology, coal self-preheating combustion has proven its potential to utilize semi-coke, anthracite and other flammable solid Fuels, which can also be applied for CGFA. In this paper, flameless mode of CGFA was achieved in a 30 kW coal self-preheating combustion test rig and the influence of air-stage method on image luminosity, temperature profiles and NOX emissions was studied. The results show that stable flameless combustion of CGFA can be easily established, and in the combustion zone, the image luminosity is uniform and no obvious flame fronts can be observed. Compared with flame mode, the combustion zone is enlarged in flameless mode and the temperature profile is more uniform. The effect of the tertiary air Nozzle position on temperature profiles is greater than that of the secondary air equivalence ratio. And with the increase of λ2, the temperatures of zone close to the preheated Fuel Nozzle decrease. The oxygen concentration along the axis of the down-fired combustor is uniform with the peak value less than 6 vol% for all cases. The exit NOX emissions can be lowered down a lot for flameless combustion, and the general emissions are less than 100 mg/Nm3 (@ 6% O2) with the lowest value even less than 50 mg/Nm3 (@ 6% O2).
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Experimental study on combustion, flame and NOX emission of pulverized coal preheated by a preheating burner
Fuel Processing Technology, 2018Co-Authors: Ziqu OuyangAbstract:Abstract Experimental researches on combustion characteristics of pulverized Ningdong bitumite preheated by a preheating burner were carried out in a 0.2 MW coal preheating combustion test rig, and the effects of preheating temperature, secondary air equivalence ratio and the positions of tertiary air Nozzles on combustion, flame and NOX emissions of preheated Fuels were studied. The results showed that the 0.2 MW coal preheating combustion test rig can operate stably and the combustion efficiency can be higher than 97% while the NOX emissions are lower than 100 mg/Nm3. With the increase of preheating temperature, NOX emissions increase, and the combustion efficiency does not change obviously. With the increase of secondary air equivalence ratio, the combustion efficiency increases, and NOX emissions increase as well. With the increase of the distance between the tertiary air Nozzle and the preheated Fuel Nozzle, NOX emissions decrease, and the combustion efficiency decreases as well. The flame characteristic is not sensitive to preheating temperature, but closely related to the air distribution of down-fired combustor. With reasonable air supply positions, flameless combustion can be realized.
Yoji Kurosawa - One of the best experts on this subject based on the ideXlab platform.
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emission reduction of Fuel staged aircraft engine combustor using an additional premixed Fuel Nozzle
Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2013Co-Authors: Takeshi Yamamoto, Kazuo Shimodaira, Seiji Yoshida, Yoji KurosawaAbstract:NOx emissions from aircraft engines cause atmospheric pollution near airports. In addition, in the troposphere, NOx reacts with hydrocarbons in the presence of sunlight to form ozone, which is a powerful greenhouse gas, and thus NOx is a secondary greenhouse gas [1]. There is a trend of increasing the pressure ratio in aircraft engines, since this trend reduces the Fuel consumption and emission of the most important greenhouse gas, CO2. However, NOx increases with pressure ratio, thereby making the reduction in NOx in future aircraft engines more difficult. Air transportation volume will increase in the future. Therefore, the development of technologies to reduce NOx emissions from aircraft engines is very important. ICAO CAEP has tightened the NOx emission standard, as shown in Fig. Fig.1.1. Engine data were taken from the ICAO Aircraft Engine Emissions Databank [2]. Engine manufacturers and national research institutes are actively working on low-NOx technologies to meet lower NOx emission standards. In Japan, research and development of environmentally compatible engines for small aircraft (ECO engine project) [3] is being conducted. The thrust range of the engine is 8000–12,000 pounds. For this project, IHI, Kawasaki Heavy Industries, and Mitsubishi Heavy Industries developed three low-NOx combustors using different combustion types that were aimed at a 50% reduction over the CAEP/4 standard. Fig. 1 ICAO NOx standard and target of TechCLEAN Rolls-Royce Deutschland is developing a core engine with a 65% reduction over the CAEP/2 NOx standard and proved a 70% reduction in a full annular combustor in the Engine 3E (Environment, Economy, and Efficiency) program [4]. Advisory Council for Aeronautics Research in Europe (ACARE) aims at an 80% reduction in NOx emission in its vision for aeronautics in the year 2020, Vision 2020. In the United States, the NASA Environmentally Responsible Aviation (ERA) project is also underway [5]. It aims at a 75% reduction over the CAEP/6 NOx standard. General Electric developed a lean-staged combustor, namely twin annular premixing swirler (TAPS) combustor, and applied it to a new practical engine, GEnx. The Japan Aerospace Exploration Agency (JAXA) started TechCLEAN [6] in October 2003 for conducting research and development of aircraft engine technologies to reduce environmental impact. In this project, technologies for noise, NOx and CO2 reduction are being developed. The target for NOx emissions is an 80% reduction over the ICAO CAEP/4 standard. For this drastic reduction in NOx emissions, a Fuel Nozzle based on the lean-staged combustion concept was designed. It has a pilot Fuel injector for diffusion combustion at the center of the Fuel Nozzle and a main Fuel–air mixer for lean premixed combustion around the pilot. Geometric variations of the main swirler were investigated in a single-sector combustor rig under four conditions of the LTO cycle of ECO engine [7]. A Fuel Nozzle, so-called model E, which was characterized by a triple contrary swirler, showed the best low-NOx performance. The test results showed that the NOx emission of the Fuel Nozzle was a 72% reduction over the ICAO CAEP/4 standard. This Fuel Nozzle was also tested in a multisector combustor under the same conditions [8]. The combustor is 3/16th the size of a small annular combustor and has three Fuel Nozzles. The test results showed that the combustor had combustion characteristics equivalent to a 70% reduction over the CAEP/4 NOx standard, which was almost the same as that of the single-sector combustor. For improvement of combustion efficiency (CE) under the middle power conditions of the engine, Fuel staging among the main Fuel mixers was investigated. The results showed that Fuel staging was effective in improving the CE of the annular combustor. As a next step, the Fuel Nozzle was tested in the single-sector combustor rig under the four conditions of the LTO cycle of an assumed engine [9]. The engine has a rated output of 40 kN and an overall pressure ration (OPR) of 25.8. Test results showed that the combustor has a NOx emission, which is a 77% reduction over CAEP/4. However, a reduction in smoke emissions under thrust conditions higher than the 30% MTO condition and a reduction in CO emissions under thrust conditions lower than the 85% MTO condition are necessary. In this study, an additional Fuel Nozzle, called the emissions control Fuel Nozzle (ECF), was designed to reduce NOx, smoke, and CO emissions. The single-sector combustor with the lean-staged Fuel Nozzle (LSF) and the additional Fuel Nozzle was tested.
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emission reduction of Fuel staged aircraft engine combustor using an additional premixed Fuel Nozzle
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, 2012Co-Authors: Takeshi Yamamoto, Kazuo Shimodaira, Seiji Yoshida, Yoji KurosawaAbstract:The Japan Aerospace Exploration Agency (JAXA) is conducting research and development on aircraft engine technologies to reduce environmental impact for the TechCLEAN project. As a part of the project, combustion technologies have been developed with an aggressive target that is an 80% reduction over the NOx threshold of the ICAO CAEP/4 standard. A staged Fuel Nozzle with a pilot mixer and a main mixer was developed and tested using a single-sector combustor under the target engine’s LTO cycle conditions with a rated output of 40 kN and an overall pressure ratio of 25.8. The test results showed a 77% reduction over the CAEP/4 NOx standard. A reduction in smoke was found under a higher thrust condition than the 30% MTO condition, and a reduction in CO emission was found under a lower thrust condition than the 85% MTO condition. In the present study, an additional Fuel burner was designed and tested with the staged Fuel Nozzle in a single-sector combustor to control emissions. The test results show that the combustor enables an 82% reduction in NOx emissions relative to the ICAO CAEP/4 standard and a drastic reduction in smoke and CO emissions.Copyright © 2012 by ASME
Peter Weigand - One of the best experts on this subject based on the ideXlab platform.
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investigations of swirl flames in a gas turbine model combustor i flow field structures temperature and species distributions
Combustion and Flame, 2006Co-Authors: Peter Weigand, Wolfgang Meier, Xuru Duan, W Stricker, Manfred AignerAbstract:Abstract A gas turbine model combustor for swirling CH 4 /air diffusion flames at atmospheric pressure with good optical access for detailed laser measurements is discussed. Three flames with thermal powers between 7.6 and 34.9 kW and overall equivalence ratios between 0.55 and 0.75 were investigated. These behave differently with respect to combustion instabilities: Flame A burned stably, flame B exhibited pronounced thermoacoustic oscillations, and flame C, operated near the lean extinction limit, was subject to sudden liftoff with partial extinction and reanchoring. One aim of the studies was a detailed experimental characterization of flame behavior to better understand the underlying physical and chemical processes leading to instabilities. The second goal of the work was the establishment of a comprehensive database that can be used for validation and improvement of numerical combustion models. The flow field was measured by laser Doppler velocimetry, the flame structures were visualized by planar laser-induced fluorescence (PLIF) of OH and CH radicals, and the major species concentrations, temperature, and mixture fraction were determined by laser Raman scattering. The flow fields of the three flames were quite similar, with high velocities in the region of the injected gases, a pronounced inner recirculation zone, and an outer recirculation zone with low velocities. The flames were not attached to the Fuel Nozzle and thus were partially premixed before ignition. The near field of the flames was characterized by fast mixing and considerable finite-rate chemistry effects. CH PLIF images revealed that the reaction zones were thin (⩽0.5 mm) and strongly corrugated and that the flame zones were short ( h ⩽ 50 mm ). Despite the similar flow fields of the three flames, the oscillating flame B was flatter and opened more widely than the others. In the current article, the flow field, structures, and mean and rms values of the temperature, mixture fraction, and species concentrations are discussed. Turbulence intensities, mixing, heat release, and reaction progress are addressed. In a second article, the turbulence–chemistry interactions in the three flames are treated.
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investigations of swirl flames in a gas turbine model combustor ii turbulence chemistry interactions
Combustion and Flame, 2006Co-Authors: Wolfgang Meier, Xuru Duan, Peter WeigandAbstract:A gas turbine model combustor for swirling CH{sub 4}/air diffusion flames at atmospheric pressure with good optical access for detailed laser measurements is discussed. Three flames with thermal powers between 7.6 and 34.9 kW and overall equivalence ratios between 0.55 and 0.75 were investigated. These behave differently with respect to combustion instabilities: Flame A burned stably, flame B exhibited pronounced thermoacoustic oscillations, and flame C, operated near the lean extinction limit, was subject to sudden liftoff with partial extinction and reanchoring. One aim of the studies was a detailed experimental characterization of flame behavior to better understand the underlying physical and chemical processes leading to instabilities. The second goal of the work was the establishment of a comprehensive database that can be used for validation and improvement of numerical combustion models. The flow field was measured by laser Doppler velocimetry, the flame structures were visualized by planar laser-induced fluorescence (PLIF) of OH and CH radicals, and the major species concentrations, temperature, and mixture fraction were determined by laser Raman scattering. The flow fields of the three flames were quite similar, with high velocities in the region of the injected gases, a pronounced inner recirculation zone, and an outer recirculation zonemore » with low velocities. The flames were not attached to the Fuel Nozzle and thus were partially premixed before ignition. The near field of the flames was characterized by fast mixing and considerable finite-rate chemistry effects. CH PLIF images revealed that the reaction zones were thin (=<0.5 mm) and strongly corrugated and that the flame zones were short (h=<50 mm). Despite the similar flow fields of the three flames, the oscillating flame B was flatter and opened more widely than the others. In the current article, the flow field, structures, and mean and rms values of the temperature, mixture fraction, and species concentrations are discussed. Turbulence intensities, mixing, heat release, and reaction progress are addressed. In a second article, the turbulence-chemistry interactions in the three flames are treated.« less
Ron Zevenhoven - One of the best experts on this subject based on the ideXlab platform.
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emissions from large scale medium speed diesel engines 1 influence of engine operation mode and turbocharger
Fuel Processing Technology, 2008Co-Authors: Arto Sarvi, Carljohan Fogelholm, Ron ZevenhovenAbstract:Abstract The operation of four – stroke diesel engines in either propulsion or generator mode application has a strong influence on gaseous, smoke (soot) and particulates emissions. Tests were made with a supercharged after-cooled large-scale diesel engine (mean speed ∼ 500 rpm, power per cylinder ∼ 1 MW) burning mainly heavy Fuel oil. Gaseous emissions (NOx, CO, HC) were measured according to the IMO technical code, smoke (soot) emissions were determined optically and particulate matter (PM) was measured using a gravimetric impactor for five size fractions. Impact on gaseous emissions, smoke (soot) and PM was found when analysing the effects of the engine operating mode, Fuel Nozzle, start of injection (SOI), and load (speed). Results show that the exhaust emission was also highly dependent on the engine turbocharger system, especially the by-pass control, but was not affected by waste gate control. The gaseous and soot emissions were less for the generator mode in the total load region, decreasing with the load. PM emissions were found to decrease with the load for the propulsion mode, while showing an increase with the load for the generator mode.
Kazuo Shimodaira - One of the best experts on this subject based on the ideXlab platform.
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emission reduction of Fuel staged aircraft engine combustor using an additional premixed Fuel Nozzle
Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2013Co-Authors: Takeshi Yamamoto, Kazuo Shimodaira, Seiji Yoshida, Yoji KurosawaAbstract:NOx emissions from aircraft engines cause atmospheric pollution near airports. In addition, in the troposphere, NOx reacts with hydrocarbons in the presence of sunlight to form ozone, which is a powerful greenhouse gas, and thus NOx is a secondary greenhouse gas [1]. There is a trend of increasing the pressure ratio in aircraft engines, since this trend reduces the Fuel consumption and emission of the most important greenhouse gas, CO2. However, NOx increases with pressure ratio, thereby making the reduction in NOx in future aircraft engines more difficult. Air transportation volume will increase in the future. Therefore, the development of technologies to reduce NOx emissions from aircraft engines is very important. ICAO CAEP has tightened the NOx emission standard, as shown in Fig. Fig.1.1. Engine data were taken from the ICAO Aircraft Engine Emissions Databank [2]. Engine manufacturers and national research institutes are actively working on low-NOx technologies to meet lower NOx emission standards. In Japan, research and development of environmentally compatible engines for small aircraft (ECO engine project) [3] is being conducted. The thrust range of the engine is 8000–12,000 pounds. For this project, IHI, Kawasaki Heavy Industries, and Mitsubishi Heavy Industries developed three low-NOx combustors using different combustion types that were aimed at a 50% reduction over the CAEP/4 standard. Fig. 1 ICAO NOx standard and target of TechCLEAN Rolls-Royce Deutschland is developing a core engine with a 65% reduction over the CAEP/2 NOx standard and proved a 70% reduction in a full annular combustor in the Engine 3E (Environment, Economy, and Efficiency) program [4]. Advisory Council for Aeronautics Research in Europe (ACARE) aims at an 80% reduction in NOx emission in its vision for aeronautics in the year 2020, Vision 2020. In the United States, the NASA Environmentally Responsible Aviation (ERA) project is also underway [5]. It aims at a 75% reduction over the CAEP/6 NOx standard. General Electric developed a lean-staged combustor, namely twin annular premixing swirler (TAPS) combustor, and applied it to a new practical engine, GEnx. The Japan Aerospace Exploration Agency (JAXA) started TechCLEAN [6] in October 2003 for conducting research and development of aircraft engine technologies to reduce environmental impact. In this project, technologies for noise, NOx and CO2 reduction are being developed. The target for NOx emissions is an 80% reduction over the ICAO CAEP/4 standard. For this drastic reduction in NOx emissions, a Fuel Nozzle based on the lean-staged combustion concept was designed. It has a pilot Fuel injector for diffusion combustion at the center of the Fuel Nozzle and a main Fuel–air mixer for lean premixed combustion around the pilot. Geometric variations of the main swirler were investigated in a single-sector combustor rig under four conditions of the LTO cycle of ECO engine [7]. A Fuel Nozzle, so-called model E, which was characterized by a triple contrary swirler, showed the best low-NOx performance. The test results showed that the NOx emission of the Fuel Nozzle was a 72% reduction over the ICAO CAEP/4 standard. This Fuel Nozzle was also tested in a multisector combustor under the same conditions [8]. The combustor is 3/16th the size of a small annular combustor and has three Fuel Nozzles. The test results showed that the combustor had combustion characteristics equivalent to a 70% reduction over the CAEP/4 NOx standard, which was almost the same as that of the single-sector combustor. For improvement of combustion efficiency (CE) under the middle power conditions of the engine, Fuel staging among the main Fuel mixers was investigated. The results showed that Fuel staging was effective in improving the CE of the annular combustor. As a next step, the Fuel Nozzle was tested in the single-sector combustor rig under the four conditions of the LTO cycle of an assumed engine [9]. The engine has a rated output of 40 kN and an overall pressure ration (OPR) of 25.8. Test results showed that the combustor has a NOx emission, which is a 77% reduction over CAEP/4. However, a reduction in smoke emissions under thrust conditions higher than the 30% MTO condition and a reduction in CO emissions under thrust conditions lower than the 85% MTO condition are necessary. In this study, an additional Fuel Nozzle, called the emissions control Fuel Nozzle (ECF), was designed to reduce NOx, smoke, and CO emissions. The single-sector combustor with the lean-staged Fuel Nozzle (LSF) and the additional Fuel Nozzle was tested.
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emission reduction of Fuel staged aircraft engine combustor using an additional premixed Fuel Nozzle
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, 2012Co-Authors: Takeshi Yamamoto, Kazuo Shimodaira, Seiji Yoshida, Yoji KurosawaAbstract:The Japan Aerospace Exploration Agency (JAXA) is conducting research and development on aircraft engine technologies to reduce environmental impact for the TechCLEAN project. As a part of the project, combustion technologies have been developed with an aggressive target that is an 80% reduction over the NOx threshold of the ICAO CAEP/4 standard. A staged Fuel Nozzle with a pilot mixer and a main mixer was developed and tested using a single-sector combustor under the target engine’s LTO cycle conditions with a rated output of 40 kN and an overall pressure ratio of 25.8. The test results showed a 77% reduction over the CAEP/4 NOx standard. A reduction in smoke was found under a higher thrust condition than the 30% MTO condition, and a reduction in CO emission was found under a lower thrust condition than the 85% MTO condition. In the present study, an additional Fuel burner was designed and tested with the staged Fuel Nozzle in a single-sector combustor to control emissions. The test results show that the combustor enables an 82% reduction in NOx emissions relative to the ICAO CAEP/4 standard and a drastic reduction in smoke and CO emissions.Copyright © 2012 by ASME
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suppression of nox emission of a lean staged combustor for an aircraft engine
ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition, 2011Co-Authors: Hitoshi Fujiwara, Kazuo Shimodaira, Kazuaki Matsuura, Shigeru Hayashi, Masayoshi Kobayashi, Takeo Oda, Atsushi Horikawa, R Matsuyama, Hideki Ogata, Yasuhiro KinoshitaAbstract:Due to the increasing demands for environment protection, the regulation of NOx emissions from aircraft engines specified by ICAO have become more stringent year by year. A combustor with lean staged Fuel injectors is one of the effective methods to reduce NOx emissions. Kawasaki heavy industries Ltd GTBC and Japan Aerospace Exploration Agency (JAXA) have been conducting joint research on a lean staged concentric Fuel Nozzle for a high pressure ratio aero engine. High pressure combustion tests were performed to clarify the effect of the contour of the air flow passage of the main premix duct, the arrangement of the swilers and the Fuel injection position on the NOx emission especially at high power. Visualization of the Fuel spray at elevated pressure inside of the premix duct using a model with transparent walls and a laser diagnostics technique showed clear relationship between the distribution of the Fuel spray and the NOx emission.Copyright © 2011 by ASME
