Experimental Study on Laser-Induced Ignition of Swirl-Stabilized Kerosene Flames

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Klaus G. Moesl ◽  
Klaus G. Vollmer ◽  
Thomas Sattelmayer ◽  
Johannes Eckstein ◽  
Herbert Kopecek
Keyword(s):  
Combustion Chamber ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Focal Point ◽  
Central Zone ◽  
Laser Ignition ◽  
Spark Plug ◽  
Parametric Testing ◽  
Induced Ignition ◽  
Ignition Kernel

Conventional ignition systems of aeroengines are an integral part of the combustion chamber’s structure. Due to this hardware-related constraint, the ignition spark has to be generated in the quench zone of the combustion chamber, which is far from the optimum regarding thermo- and aerodynamics. An improved ignitability of the fuel-air mixture can be found in the central zone of the combustor, where higher local equivalence ratios prevail and where mixing is favorable for a smooth ignition. It would be a major advancement in aeroengine design to position the ignition kernel in these zones. A laser system is able to ignite the fuel-air mixture at almost any location inside of the combustion chamber. Commercial laser systems are under development, which can replace conventional spark plugs in internal combustion engines and gas turbines. This study was conducted to evaluate the applicability of laser ignition in liquid-fueled aeroengines. Ignition tests were performed with premixed natural gas and kerosene to evaluate the different approaches of laser and spark plug ignition. The experiments were carried out on a generic test rig with a well-investigated swirler, allowing sufficient operational flexibility for parametric testing. The possibility of the free choice of the laser’s focal point is the main advantage of laser-induced ignition. Placing the ignition kernel at the spray cone’s shear layer or at favorable locations in the recirculation zone could significantly increase the ignitability of the system. Consequently, the laser ignition of atomized kerosene was successfully tested down to a global equivalence ratio of 0.23. Furthermore, the laser outperformed the spark plug at ignition locations below axial distances of 50 mm from the spray nozzle.

Experimental Study on Laser-Induced Ignition of Swirl-Stabilized Kerosene Flames

2008 ◽  
Author(s):  
Klaus G. Moesl ◽  
Klaus G. Vollmer ◽  
Thomas Sattelmayer ◽  
Johannes Eckstein ◽  
Herbert Kopecek
Keyword(s):  
Combustion Chamber ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Central Zone ◽  
Laser Ignition ◽  
Spark Plug ◽  
Parametric Testing ◽  
Aero Engines ◽  
Induced Ignition ◽  
Ignition Kernel

Conventional ignition systems of aero-engines are an integral part of the combustion chamber’s structure. Due to this hardware-related constraint, the ignition spark has to be generated in the quench zone of the combustion chamber, which is far from the optimum regarding thermo- and aerodynamics. An improved ignitability of the fuel-air mixture can be found in the central zone of the combustor, where higher local equivalence ratios prevail and where mixing is favorable for a smooth ignition. It would be a major advancement in aero-engine design to position the ignition kernel in these zones. A laser system is able to ignite the fuel-air mixture at almost any location inside of the combustion chamber. Commercial laser systems are under development, which can replace conventional spark plugs in internal combustion engines and gas turbines. This study was conducted to evaluate the applicability of laser ignition in liquid-fueled aero-engines. Ignition tests were performed with premixed natural gas and kerosene to evaluate the different approaches of laser and spark plug ignition. The experiments were carried out on a generic test rig with a well-investigated swirler, allowing sufficient operational flexibility for parametric testing. The possibility of the free choice of the laser’s focal point is the main advantage of laser-induced ignition. Placing the ignition kernel at the spray cone’s shear layer or at favorable locations in the recirculation zone could significantly increase the ignitability of the system. Consequently, the laser ignition of atomized kerosene was successfully tested down to a global equivalence ratio of 0.23. Furthermore, the laser outperformed the spark plug at ignition locations below axial distances of 50 mm from the spray nozzle.

Review of Laser Ignition for Methane-Air Mixtures

2015 ◽  
Vol 727-728 ◽  
pp. 592-596
Author(s):  
Hong Tao Wang ◽  
Cang Su Xu
Keyword(s):  
Fuel Consumption ◽  
Internal Combustion Engines ◽  
Pollutant Emissions ◽  
Laser Ignition ◽  
Combustion Engines ◽  
Ignition System ◽  
Spark Plug ◽  
Induced Ignition ◽  
Ignition And Combustion ◽  
Promising Development

Reducing vehicle pollutant emissions and fuel consumption is becoming more and more important challenges, while lean-burning are a promising development. However, lean-burning may leads to other problems including combustion instability and incomplete combustion. Recently, laser ignition system has become an attractive field of research in order to replace the conventional spark plug ignition systems in the internal combustion engines to solve problem above. Moreover, methane was regarded as very promising fuel. Therefore, the objective of this article is to review the ignition and combustion characteristics of methane-air mixtures by laser-induced ignition.

MULTIFOCAL IGNITION OF COMBUSTION CHAMBER BY SUBCRITICAL STREAMER MICROWAVE DISCHARGE

2020 ◽  
Author(s):  
P. V. Bulat ◽  
◽  
M. P. Bulat ◽  
P. V. Denissenko ◽  
V. V. Upyrev ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Microwave Discharge ◽  
Fuel Mixture ◽  
Combustion Products ◽  
Combustion Chambers ◽  
Entire Volume ◽  
Gas Pumping ◽  
Pumping Units

The challenges facing engine developers, aimed at improving the technical and operational characteristics, more stringent environmental standards, make the work aimed at increasing the efficiency of ignition, systems highly relevant. Technologies of prechamber, arc ignition, and ignition by corona discharge known to date require significant energy costs. In addition, ignition of a fuel mixture by such systems is local which leads to the limitation in the burning rate, incomplete combustion of fuel, and formation of harmful impurities in combustion products. Volumetric or multipoint ignition may significantly increase the effectiveness of the use of ignition systems. The use of a subcritical streamer microwave discharge, which is a network of thin hot channels propagating in the volume of the combustion chamber, seems promising because it provides virtually instantaneous ignition of the mixture in the entire volume. In this paper, the results of experiments using a subcritical streamer microwave discharge are presented. The possibility of volumetric ignition and a substantial increase in the completeness of fuel combustion is demonstrated. A number of indirect evidences indicate the absence of nitrogen oxides in combustion products. The results can be applied to the development of multivolumetric ignition systems in internal combustion engines, gas pumping units, power gas turbines, low-emission combustion chambers, etc.

Laser Ignition, Optics and Contamination of Optics in an I.C. Engine

2004 ◽  
Author(s):  
Josef Graf ◽  
Martin Weinrotter ◽  
Herbert Kopecek ◽  
Ernst Wintner
Keyword(s):  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Laser Energy ◽  
Direct Injection ◽  
Combustion Process ◽  
Exhaust Emission ◽  
Ignition System ◽  
Term Operation ◽  
Self Cleaning ◽  
Induced Ignition

Due to the progresses in exhaust emission after-treatment systems and in the development of new combustion processes, the S.I. engine has been booming in the past few years. But the efficiency will have to be improved in the future. Because of its thermodynamic benefits, the S.I. direct injection engine of the second generation — so called air guided system — shows the highest potential for gasoline engines to reduce fuel consumption. However, there are restrictions when using conventional spark ignition system. They concern the optimum position of ignition initialization and spark-plug wear, the latter being caused by inhomogeneous mixture distribution. The laser-induced ignition enables a flexible choice of the ignition location and a wear resistant initialization of the combustion process. The most crucial component here is the optics (the combustion-chamber window), through which the laser beam passes into the combustion chamber. In this paper, laser-induced ignition is discussed and its potential compared to a conventional ignition system is presented. In addition, several optic configurations are presented as well as tests regarding the minimum required laser energy and the optic contamination and self-cleaning effect of the optics. At the Institute of Internal Combustion Engines at the Vienna University of Technology the optic contamination and self-cleaning effect, which is crucial for a long-term operation, was tested on a two-cylinder research engine.

Laser Ignition of Methane-Air Mixtures at High Pressures and Diagnostics

2005 ◽  
Vol 127 (1) ◽  
pp. 213-219 ◽  
Author(s):  
Herbert Kopecek ◽  
Soren Charareh ◽  
Maximilian Lackner ◽  
Christian Forsich ◽  
Franz Winter ◽  
...  
Keyword(s):  
Natural Gas ◽  
Nd:Yag Laser ◽  
High Pressures ◽  
Laser Energy ◽  
Spectroscopic Technique ◽  
Laser Ignition ◽  
Pulsed Nd:Yag Laser ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Induced Ignition

Methane-air mixtures at high fill pressures up to 30 bar and high temperatures up to 200°C were ignited in a high-pressure chamber with automated fill control by a 5 ns pulsed Nd:YAG laser at 1064 nm wavelength. Both, the minimum input laser pulse energy for ignition and the transmitted fraction of energy through the generated plasma were measured as a function of the air/fuel-equivalence ratio (λ). The lean-side ignition limit of methane-air mixtures was found to be λ=2.2. However, only λ<2.1 seems to be practically usable. As a comparison, the limit for conventional spark plug ignition of commercial natural gas engines is λ=1.8. Only with excessive efforts λ=2.0 can be spark ignited. The transmitted pulse shape through the laser-generated plasma was determined temporally as well as its dependence on input laser energy and properties of the specific gases interacting. For a first demonstration of the practical applicability of laser ignition, one cylinder of a 1 MW natural gas engine was ignited by a similar 5 ns pulsed Nd:YAG laser at 1064 nm. The engine worked successfully at λ=1.8 for a first test period of 100 hr without any interruption due to window fouling and other disturbances. Lowest values for NOx emission were achieved at λ=2.05 NOx=0.22 g/KWh. Three parameters obtained from accompanying spectroscopic measurements, namely, water absorbance, flame emission, and the gas inhomogeneity index have proven to be powerful tools to judge laser-induced ignition of methane-air mixtures. The following effects were determined by the absorption spectroscopic technique: formation of water in the vicinity of the laser spark (semi-quantitative); characterization of ignition (ignition delay, incomplete ignition, failed ignition); homogeneity of the gas phase in the vicinity of the ignition; and the progress of combustion.

Laser Ignition of Methane-Air Mixtures at High Pressures and Diagnostics

2003 ◽  
Author(s):  
Herbert Kopecek ◽  
Soren Charareh ◽  
Max Lackner ◽  
Christian Forsich ◽  
Franz Winter ◽  
...  
Keyword(s):  
Natural Gas ◽  
Nd:Yag Laser ◽  
High Pressures ◽  
Laser Energy ◽  
Spectroscopic Technique ◽  
Laser Ignition ◽  
Pulsed Nd:Yag Laser ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Induced Ignition

Methane-air mixtures at high fill pressures up to 30 bar and high temperatures up to 200 °C were ignited in a high pressure chamber with automated fill control by a 5 ns pulsed Nd:YAG laser at 1064 nm wavelength. Both, the minimum input laser pulse energy for ignition and the transmitted fraction of energy through the generated plasma were measured as a function of the air/fuel-equivalence ratio (λ). The lean side ignition limit of methane-air mixtures was found to be λ = 2.4. However, only λ < 2.2 seems to be practically usable. As a comparison, the limit for conventional spark plug ignition of commercial natural gas engines is λ = 1.8. Only with excessive efforts λ = 2.0 can be spark-ignited. The transmitted pulse shape through the laser-generated plasma was determined temporally as well as its dependence on input laser energy and properties of the specific gases interacting. For a first demonstration of the practical applicability of laser ignition, one cylinder of a 1 MW natural gas engine was ignited by a similar 5 ns pulsed Nd:YAG laser at 1064 nm. The engine worked successfully at λ = 1.8 for a first test period of 100 hours without any interruption due to window fouling and other disturbances. Lowest values for NOx emission were achieved at λ = 2.05 (NOx = 0.22 g/KWh). Three parameters obtained from accompanying spectroscopic measurements, namely water absorbance, flame emission and the gas inhomogeneity index have proven to be a powerful tool to judge laser-induced ignition of methane-air mixtures. The following effects were determined by the absorption spectroscopic technique: formation of water in the vicinity of the laser spark (semi-quantitative); characterization of ignition (ignition delay, incomplete ignition, failed ignition); homogeneity of the gas phase in the vicinity of the ignition and the progress of combustion.

Optical Diagnostics of Laser Ignition for Future Advanced Engines

2004 ◽  
Author(s):  
Maximilian Lackner ◽  
Franz Winter ◽  
Soren Charareh ◽  
Kurt Iskra ◽  
Theo Neger ◽  
...  
Keyword(s):  
Shock Wave ◽  
Flame Front ◽  
Pulse Energy ◽  
Internal Combustion Engines ◽  
High Pressures ◽  
Optical Diagnostics ◽  
Laser Induced Fluorescence ◽  
Laser Ignition ◽  
Spark Plug ◽  
Schlieren Photography

A laser-based system should be advantageous to a spark-plug based ignition system. Free choice of the ignition spot and precise timing constitute two major advantages. Multi point laser ignition could lead to higher efficiencies, and laser ignition as such is capable of igniting leaner mixtures than a spark plug, thereby decreasing thermal NOx and soot emissions. This paper is devoted to advances in optical diagnostics of laser ignition for future internal combustion engines. The focus of this paper is on diagnostics at high pressures, that is engine-like conditions. Laser ignition tests were performed with the fuels methane, hydrogen and biogas in static combustion cells with dimensions comparable to stationary engines. A Nd:YAG laser (5 ns pulse duration, wavelength 1064 nm, 1–20 mJ pulse energy) was used to ignite gaseous fuel/air mixtures at initial pressures of 1–3 MPa. Schlieren photography and laser-induced fluorescence (LIF) were used for optical diagnostics (flame kernel development, shock wave propagation). The lean burn characteristics were investigated. Schlieren photography was used to determine the velocity of the shock wave and to study the influence of the shock wave on temperature rise and energy loss. Using planar laser-induced fluorescence (PLIF), the spatial distribution of the combustion intermediates OH and formaldehyde were recorded. The temporally resolved imaging shows that the initial stages of the flame front evolution closely follows the turbulence and density fluctuations caused by the shock and pressure wave induced by the laser spark. In this paper, results from LIF spectroscopy and Schlieren photography are compared. Depending on the laser pulse energy and focus size, at later stages after the ignition the flame front propagation approaches the laminar burning regime and flame front speed decrease. Flame front break up at lean conditions indicates the limit of the ignitable mixture fraction when the speed due to spark-induced convection exceeds the flame propagation rate.

https://elibrary.ru/item.asp?id=44369782&pf=1

2020 ◽  
Author(s):  
QI CHEN ◽  
◽  
JINTAO SUN ◽  
JIANYU LIU ◽  
BAOMING ZHAO ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Nonequilibrium Plasma ◽  
Combustible Mixture ◽  
Combustion Engines ◽  
Combustion Chemistry ◽  
Microwave Radio ◽  
Different Types ◽  
Gas Molecules ◽  
Ignition And Combustion

Plasma-assisted ignition and combustion, widely applied in gas turbines, scramjets, and internal combustion engines, has been considered as a promising technique in shortening ignition delay time, improving combustion energy efficiency, and reducing emission. Nonequilibrium plasma can excite the gas molecules to higher energy states, directly dissociate or ionize the molecules and, thereby, has the potential to produce reactive species at residence time and location in a combustible mixture and then to efficiently accelerate the overall pyrolysis, oxidation, and ignition. Previous studies have demonstrated the effectiveness of plasma-assisted combustion by using direct current, alternating currant, microwave, radio frequency, and pulsed nanosecond discharge (NSD). Due to the complicated interaction between plasma and combustion in different types of plasma, detailed plasma-combustion chemistry is still not well understood.

scholarly journals Laminar Burning Velocity of Biogas-Containing Mixtures. A Literature Review

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 996
Author(s):  
Venera Giurcan ◽  
Codina Movileanu ◽  
Adina Magdalena Musuc ◽  
Maria Mitu
Keyword(s):  
Gas Turbines ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Combustion Engine ◽  
Burning Velocity ◽  
Internal Combustion ◽  
Electricity Production ◽  
Engine Fuel ◽  
Laminar Burning Velocity ◽  
Waste Products

Currently, the use of fossil fuels is very high and existing nature reserves are rapidly depleted. Therefore, researchers are turning their attention to find renewable fuels that have a low impact on the environment, to replace these fossil fuels. Biogas is a low-cost alternative, sustainable, renewable fuel existing worldwide. It can be produced by decomposition of vegetation or waste products of human and animal biological activity. This process is performed by microorganisms (such as methanogens and sulfate-reducing bacteria) by anaerobic digestion. Biogas can serve as a basis for heat and electricity production used for domestic heating and cooking. It can be also used to feed internal combustion engines, gas turbines, fuel cells, or cogeneration systems. In this paper, a comprehensive literature study regarding the laminar burning velocity of biogas-containing mixtures is presented. This study aims to characterize the use of biogas as IC (internal combustion) engine fuel, and to develop efficient safety recommendations and to predict and reduce the risk of fires and accidental explosions caused by biogas.

scholarly journals Combustion Thermodynamics of Ethanol, n-Heptane, and n-Butanol in a Rapid Compression Machine with a Dual Direct Injection (DDI) Supply System

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2729
Author(s):  
Ireneusz Pielecha ◽  
Sławomir Wierzbicki ◽  
Maciej Sidorowicz ◽  
Dariusz Pietras
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
Internal Combustion Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Rapid Compression Machine ◽  
Process Indicators ◽  
Rapid Compression

The development of internal combustion engines involves various new solutions, one of which is the use of dual-fuel systems. The diversity of technological solutions being developed determines the efficiency of such systems, as well as the possibility of reducing the emission of carbon dioxide and exhaust components into the atmosphere. An innovative double direct injection system was used as a method for forming a mixture in the combustion chamber. The tests were carried out with the use of gasoline, ethanol, n-heptane, and n-butanol during combustion in a model test engine—the rapid compression machine (RCM). The analyzed combustion process indicators included the cylinder pressure, pressure increase rate, heat release rate, and heat release value. Optical tests of the combustion process made it possible to analyze the flame development in the observed area of the combustion chamber. The conducted research and analyses resulted in the observation that it is possible to control the excess air ratio in the direct vicinity of the spark plug just before ignition. Such possibilities occur as a result of the properties of the injected fuels, which include different amounts of air required for their stoichiometric combustion. The studies of the combustion process have shown that the combustible mixtures consisting of gasoline with another fuel are characterized by greater combustion efficiency than the mixtures composed of only a single fuel type, and that the influence of the type of fuel used is significant for the combustion process and its indicator values.

Sign in / Sign up

Export Citation Format

Share Document