Aircraft Gas Turbine Emissions Challenge

1994 ◽  
Vol 116 (3) ◽  
pp. 474-477 ◽  
Author(s):  
B. L. Koff
Keyword(s):  
Fuel Efficiency ◽  
Harmful Effect ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Supersonic Aircraft ◽  
Significant Challenge ◽  
Unburned Hydrocarbon ◽  
Hc Emissions ◽  
New Generation

The new generation of jet powered aircraft faces a significant challenge to reduce pollutant emissions while increasing fuel efficiency. Carbon monoxide (CO) and unburned hydrocarbon (HC) emissions are already very low and continued control of these pollutants is expected as engine temperatures and pressure ratios are increased. In contrast, significant system design improvements are needed to reduce oxides of nitrogen (NOx) emissions because of their harmful effect on the earth’s ozone layer. This paper discusses the prospects and technical approaches for significant NOx reductions in current and future subsonic and supersonic aircraft.

scholarly journals Aircraft Gas Turbine Emissions Challenge

1993 ◽  
Author(s):  
B. L. Koff
Keyword(s):  
Fuel Efficiency ◽  
Harmful Effect ◽  
Pollutant Emissions ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Supersonic Aircraft ◽  
Significant Challenge ◽  
Unburned Hydrocarbon ◽  
Hc Emissions ◽  
New Generation

The new generation of jet powered aircraft faces a significant challenge to reduce pollutant emissions while increasing fuel efficiency. Carbon monoxide (CO) and unburned hydrocarbon (HC) emissions are already very low and continued control of these pollutants is expected as engine temperatures and pressure ratios are increased. In contrast, significant system design improvements are needed to reduce oxides of nitrogen (NOx) emissions because of their harmful effect on the earth’s ozone layer. This paper discusses the prospects and technical approaches for significant NOx reductions in current and future subsonic and supersonic aircraft.

Low Cetane Fuels in Compression Ignition Engine to Achieve LTC

2011 ◽  
Author(s):  
Swami Nathan Subramanian ◽  
Stephen Ciatti
Keyword(s):  
Low Temperature ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Fuel Efficiency ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Compression Ignition Engine ◽  
Conventional Combustion

The conventional combustion processes of Spark Ignition (SI) and Compression Ignition (CI) have their respective merits and demerits. Internal combustion engines use certain fuels to utilize those conventional combustion technologies. High octane fuels are required to operate the engine in SI mode, while high cetane fuels are preferable for CI mode of operation. Those conventional combustion techniques struggle to meet the current emissions norms while retaining high efficiency. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines, and conventional gasoline operated SI engines are not fuel efficient. Advanced combustion concepts have shown the potential to combine fuel efficiency and improved emissions performance. Low Temperature Combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Variations in injection pressures, injection schemes and Exhaust Gas Recirculation (EGR) are studied with low octane gasoline LTC. Reductions in emissions are a function of combustion phasing and local equivalence ratio. Engine speed, load, EGR quantity, compression ratio and fuel octane number are all factors that influence combustion phasing. Low cetane fuels have shown comparable diesel efficiencies with low NOx emissions at reasonably high power densities.

Experimental Investigation of CH4 and C3H8 Combustion in a Packed Bed Burner

2011 ◽  
Author(s):  
H. B. Gao ◽  
Z. G. Qu ◽  
W. Q. Tao ◽  
T. J. Lu
Keyword(s):  
Equivalence Ratio ◽  
Packed Bed ◽  
Pollutant Emissions ◽  
Flame Stability ◽  
Nox Emissions ◽  
Flame Thickness ◽  
Porous Burner ◽  
Hc Emissions ◽  
The Stability ◽  
Stability Limits

The main object of this work is to investigate combustion in a two-layer packed beds porous burner, in particular, to study the effect of methane and propane on flame stability, pressure drop and pollutant emissions. The equivalence ratio of both methane and propane varied from 0.55 to 0.70. The results indicated that flame stability limits of both methane and propane enlarged with the increasing of equivalence ratio, however, the stability limits of methane is more widely than propane. The macroscopic flame shapes of methane and propane remains approximately the same but the later has a larger flame thickness. The NOx emissions are seen to be increased and the CO decreased with the equivalence ratio, HC emissions firstly decreased and then increased with the equivalence ratio for both methane and propane.

An Experimental Investigation of Low-Octane Gasoline in Diesel Engines

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Stephen Ciatti ◽  
Swami Nathan Subramanian
Keyword(s):  
Low Temperature ◽  
Fuel Efficiency ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Conventional Combustion ◽  
Compression Ignition Engines ◽  
Temperature Combustion ◽  
Power Densities

Conventional combustion techniques struggle to meet the current emissions norms. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines. Advance combustion concepts have proved the potential to combine fuel efficiency and improved emission performance. Low-temperature combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Diesel operated LTC is limited by early knocking combustion, whereas conventional gasoline operated LTC is limited by misfiring. So the concept of using an unconventional fuel with the properties in between those two boundary fuels has been experimented in this paper. Low-octane (84 RON) gasoline has shown comparable diesel efficiencies with the lowest NOx emissions at reasonable high power densities (NOx emission was 1 g/kW h at 12 bar BMEP and 2750 rpm).

An Experimental Investigation of Low Octane Gasoline in Diesel Engines

2010 ◽  
Author(s):  
Stephen Ciatti ◽  
Swami Nathan Subramanian
Keyword(s):  
Low Temperature ◽  
Fuel Efficiency ◽  
Nox Emissions ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Oxides Of Nitrogen ◽  
Conventional Combustion ◽  
Compression Ignition Engines ◽  
Temperature Combustion ◽  
Power Densities

Conventional combustion techniques struggle to meet the current emissions norms. In particular, oxides of nitrogen (NOx) and particulate matter (PM) emissions have limited the utilization of diesel fuel in compression ignition engines. Advance combustion concepts have proved the potential to combine fuel efficiency and improved emissions performance. Low Temperature Combustion (LTC) offers reduced NOx and PM emissions with comparable modern diesel engine efficiencies. The ability of premixed, low-temperature compression ignition to deliver low PM and NOx emissions is dependent on achieving optimal combustion phasing. Diesel operated LTC is limited by early knocking combustion whereas conventional gasoline operated LTC is limited by misfiring. So the concept of using an unconventional fuel with the properties in between those two boundary fuels has been experimented in this paper. Low octane (84 RON) gasoline has shown comparable diesel efficiencies with lowest NOx emissions at reasonable high power densities (NOx emission were 1 g/kW-hr at 12 bar BMEP and 2750 rpm).

scholarly journals The Role of Fuel Preparation in Low Emissions Combustion

1995 ◽  
Author(s):  
A. H. Lefebvre
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Injection ◽  
Flame Temperature ◽  
Pollutant Emissions ◽  
Alternative Methods ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Lean Burn ◽  
The Impact

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 ultra-low NOx has become the foremost marketing issue. This paper is devoted primarily to current and emerging technologies in the development of ultra-low 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 impact 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 ultra-low NOx combustors are reviewed. At the present time lean, premix, prevaporize, combustion appears to be the only technology available for achieving ultra-low 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 ultra-low NOx emissions, notably the rich-bum, 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 which are 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.

The Role of Fuel Preparation in Low-Emission Combustion

1995 ◽  
Vol 117 (4) ◽  
pp. 617-654 ◽  
Author(s):  
A. H. Lefebvre
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Injection ◽  
Flame Temperature ◽  
Acoustic Resonance ◽  
Pollutant Emissions ◽  
Alternative Methods ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Lean Burn

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.

scholarly journals Combustion Optimization for Coal Fired Power Plant Boilers Based on Improved Distributed ELM and Distributed PSO

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1036 ◽  
Author(s):  
Xinying Xu ◽  
Qi Chen ◽  
Mifeng Ren ◽  
Lan Cheng ◽  
Jun Xie
Keyword(s):  
Power Plant ◽  
Combustion Process ◽  
Optimization Method ◽  
Combustion Efficiency ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Nox Emissions ◽  
Coupling Characteristics ◽  
Learning Machine ◽  
Combustion Optimization

Increasing the combustion efficiency of power plant boilers and reducing pollutant emissions are important for energy conservation and environmental protection. The power plant boiler combustion process is a complex multi-input/multi-output system, with a high degree of nonlinearity and strong coupling characteristics. It is necessary to optimize the boiler combustion model by means of artificial intelligence methods. However, the traditional intelligent algorithms cannot deal effectively with the massive and high dimensional power station data. In this paper, a distributed combustion optimization method for boilers is proposed. The MapReduce programming framework is used to parallelize the proposed algorithm model and improve its ability to deal with big data. An improved distributed extreme learning machine is used to establish the combustion system model aiming at boiler combustion efficiency and NOx emission. The distributed particle swarm optimization algorithm based on MapReduce is used to optimize the input parameters of boiler combustion model, and weighted coefficient method is used to solve the multi-objective optimization problem (boiler combustion efficiency and NOx emissions). According to the experimental analysis, the results show that the method can optimize the boiler combustion efficiency and NOx emissions by combining different weight coefficients as needed.

scholarly journals Model-Based Control of Torque and Nitrogen Oxide Emissions in a Euro VI 3.0 L Diesel Engine through Rapid Prototyping

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1107
Author(s):  
Stefano d’Ambrosio ◽  
Roberto Finesso ◽  
Gilles Hardy ◽  
Andrea Manelli ◽  
Alessandro Mancarella ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Rapid Prototyping ◽  
Nitrogen Oxide ◽  
Thermal State ◽  
Pollutant Emissions ◽  
Computational Time ◽  
Nox Emissions ◽  
Model Based ◽  
Brake Mean Effective Pressure ◽  
The Impact

In the present paper, a model-based controller of engine torque and engine-out Nitrogen oxide (NOx) emissions, which was previously developed and tested by means of offline simulations, has been validated on a FPT F1C 3.0 L diesel engine by means of rapid prototyping. With reference to the previous version, a new NOx model has been implemented to improve robustness in terms of NOx prediction. The experimental tests have confirmed the basic functionality of the controller in transient conditions, over different load ramps at fixed engine speeds, over which the average RMSE (Root Mean Square Error) values for the control of NOx emissions were of the order of 55–90 ppm, while the average RMSE values for the control of brake mean effective pressure (BMEP) were of the order of 0.25–0.39 bar. However, the test results also highlighted the need for further improvements, especially concerning the effect of the engine thermal state on the NOx emissions in transient operation. Moreover, several aspects, such as the check of the computational time, the impact of the controller on other pollutant emissions, or on the long-term engine operations, will have to be evaluated in future studies in view of the controller implementation on the engine control unit.

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Ioannis Goulos ◽  
Fakhre Ali ◽  
Konstantinos Tzanidakis ◽  
Vassilios Pachidis ◽  
Roberto d'Ippolito
Keyword(s):  
Environmental Impact ◽  
Fuel Consumption ◽  
Comprehensive Assessment ◽  
Pollutant Emissions ◽  
Operational Performance ◽  
Civil Aviation ◽  
Accurate Estimation ◽  
Nox Emissions ◽  
Reactor Model ◽  
Stirred Reactor

This paper presents an integrated methodology for the comprehensive assessment of combined rotorcraft–powerplant systems at mission level. Analytical evaluation of existing and conceptual designs is carried out in terms of operational performance and environmental impact. The proposed approach comprises a wide-range of individual modeling theories applicable to rotorcraft flight dynamics and gas turbine engine performance. A novel, physics-based, stirred reactor model is employed for the rapid estimation of nitrogen oxides (NOx) emissions. The individual mathematical models are implemented within an elaborate numerical procedure, solving for total mission fuel consumption and associated pollutant emissions. The combined approach is applied to the comprehensive analysis of a reference twin-engine light (TEL) aircraft modeled after the Eurocopter Bo 105 helicopter, operating on representative mission scenarios. Extensive comparisons with flight test data are carried out and presented in terms of main rotor trim control angles and power requirements, along with general flight performance charts including payload-range diagrams. Predictions of total mission fuel consumption and NOx emissions are compared with estimated values provided by the Swiss Federal Office of Civil Aviation (FOCA). Good agreement is exhibited between predictions made with the physics-based stirred reactor model and experimentally measured values of NOx emission indices. The obtained results suggest that the production rates of NOx pollutant emissions are predominantly influenced by the behavior of total air inlet pressure upstream of the combustion chamber, which is affected by the employed operational procedures and the time-dependent all-up mass (AUM) of the aircraft. It is demonstrated that accurate estimation of on-board fuel supplies ahead of flight is key to improving fuel economy as well as reducing environmental impact. The proposed methodology essentially constitutes an enabling technology for the comprehensive assessment of existing and conceptual rotorcraft–powerplant systems, in terms of operational performance and environmental impact.

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