Research on the application of aviation kerosene in a direct injection rotary engine – Part 2: Spray combustion characteristics and combustion process under optimized injection strategies

Abstract In this research, n-dodecane and JW are selected as single and multi-component surrogate fuel of aviation kerosene to study the Jet-A spray combustion characteristics. The spray combustion phenomena are simulated using large eddy simulation coupled with detailed chemical reaction mechanism. Proper orthogonal decomposition method is applied to analyze the flow field characteristics, and the instantaneous velocity field are decomposed into four parts, namely the mean field, coherent field, transition field and turbulent field, respectively. The four subfields have their own characteristics. In terms of different fuels, JW has a higher intensity of coherent structures and local vortices than n-dodecane, which promotes the fuel-air mixing and improves the combustion characteristics, and the soot formation is significantly reduced. In addition, with the increase of initial temperature, the combustion is more intense, the ignition delay time is advanced, the flame lift-off length is reduced, and soot formation is increased accordingly.

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Effect of Injection Strategies on Emissions from a Pilot-Ignited Direct-Injection Natural-Gas Engine- Part I: Late Post Injection

10.4271/2017-01-0774 ◽

2017 ◽

Cited By ~ 10

Author(s):

Ethan Faghani ◽

Pooyan Kheirkhah ◽

Christopher W.J. Mabson ◽

Gordon McTaggart-Cowan ◽

Patrick Kirchen ◽

...

Keyword(s):

Natural Gas ◽

Direct Injection ◽

Post Injection ◽

Gas Engine ◽

Natural Gas Engine ◽

Engine Part ◽

Injection Strategies

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Computational studies of fuel injection strategies on natural gas combustion characteristics in direct-injection engines

Fuel ◽

10.1016/j.fuel.2020.119823 ◽

2021 ◽

Vol 288 ◽

pp. 119823

Author(s):

Kang Pan ◽

James Wallace

Keyword(s):

Natural Gas ◽

Fuel Injection ◽

Direct Injection ◽

Combustion Characteristics ◽

Computational Studies ◽

Gas Combustion ◽

Direct Injection Engines ◽

Natural Gas Combustion ◽

Injection Strategies

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Effects of ethanol injection strategies on mixture formation and combustion process in an ethanol direct injection (EDI) plus gasoline port injection (GPI) spark-ignition engine

Fuel ◽

10.1016/j.fuel.2020.117346 ◽

2020 ◽

Vol 268 ◽

pp. 117346 ◽

Cited By ~ 1

Author(s):

Yuan Zhuang ◽

Yongfei Ma ◽

Yejian Qian ◽

Qin Teng ◽

Chunmei Wang

Keyword(s):

Direct Injection ◽

Combustion Process ◽

Spark Ignition ◽

Spark Ignition Engine ◽

Mixture Formation ◽

Ethanol Injection ◽

Injection Strategies

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Effect of Injection Strategies in Diesel/NG Direct-Injection Engines on the Combustion Process and Emissions under Low-Load Operating Conditions

Energies ◽

10.3390/en13040990 ◽

2020 ◽

Vol 13 (4) ◽

pp. 990 ◽

Cited By ~ 1

Author(s):

Jinze Li ◽

Longfei Deng ◽

Jianjun Guo ◽

Min Zhang ◽

Zhenyuan Zi ◽

...

Keyword(s):

Thermal Efficiency ◽

Direct Injection ◽

Combustion Process ◽

Combustion Efficiency ◽

Operating Conditions ◽

Diffusion Combustion ◽

Combustion Mode ◽

Low Load ◽

Hc Emissions ◽

Injection Strategies

The direct injection of natural gas (NG), which is an important research direction in the development of NG engines, has the potential to improve thermal efficiency and emissions. When NG engines operate in low-load conditions, combustion efficiency decreases and hydrocarbon (HC) emissions increase due to lean fuel mixtures and slow flame propagation speeds. The effect of two combustion modes (partially premixed compression ignition (PPCI) and high pressure direct injection (HPDI)) on combustion processes was investigated by CFD (Computational Fluid Dynamics), with a focus on different injection strategies. In the PPCI combustion mode, NG was injected early in the compression stroke and premixed with air, and then the pilot diesel was injected to cause ignition near the top dead center. This combustion mode produced a faster heat release rate, but the HC emissions were higher, and the combustion efficiency was lower. In the HPDI combustion mode, the diesel was injected first and ignited, and then the NG was injected into the flame. This combustion mode resulted in higher emissions of NOx and soot, with a diffusion combustion in the cylinder. HC emissions significantly decreased. Compared with PPCI combustion, HPDI had a higher thermal efficiency.

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Flame Front and Burned Gas Characteristics for Different Split Injection Ratios and Phasing in an Optical GDI Engine

Applied Sciences ◽

10.3390/app9030449 ◽

2019 ◽

Vol 9 (3) ◽

pp. 449 ◽

Cited By ~ 5

Author(s):

Santiago Martinez ◽

Simona Merola ◽

Adrian Irimescu

Keyword(s):

Flame Front ◽

Soot Formation ◽

Direct Injection ◽

Combustion Process ◽

Pollutant Emissions ◽

Optical Data ◽

Cylinder Pressure ◽

Split Injection ◽

Gdi Engine ◽

Injection Strategies

Direct-injection in spark-ignition engines has long been recognized as a valid option for improving fuel economy, reducing CO2 emissions and avoiding knock occurrence due to higher flexibility in control strategies. However, problems associated with mixture formation are responsible for soot emissions, one of the most limiting factors of this technology. Therefore, the combustion process and soot formation were investigated with different injection strategies on a gasoline direct injection (GDI) engine. The experimental analysis was realized on an optically accessible single cylinder engine when applying single, double and triple injection strategies. Moreover, the effect of fuel delivery phasing was also scrutinized by changing the start of the injection during late intake- and early compression-strokes. The duration of injection was split in different percentages between two or three pulses, so as to obtain close to stoichiometric operation in all conditions. The engine was operated at fixed rotational speed and spark timing, with wide-open throttle. Optical diagnostics based on cycle resolved digital imaging was applied during the early and late stages of the combustion process. Detailed information on the flame front morphology and soot formation were obtained. The optical data were correlated to in-cylinder pressure traces and exhaust gas emission measurements. The results suggest that the split injection of the fuel has advantages in terms of reduction of soot formation and NOx emissions and a similar combustion performance with respect to the single injection timing. Moreover, an early injection resulted in higher rates of heat release and in-cylinder pressure, together with a reduction of soot formation and flame distortion. The double injection strategy with higher percentage of fuel injected in the first pulse and early second injection pulse showed the best results in terms of combustion evolution and pollutant emissions. For the operative condition studied, a higher time for mixture homogenization and split of fuel injected in the intake stroke shows the best results.

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