Numerical study of combustion and emission characteristics of dual-fuel engines using 3D-CFD models coupled with chemical kinetics

Dual-fuel engines at part loads inevitably suffer from lower thermal efficiency and higher carbon monoxide and unburned fuel emission. The present work was carried out to investigate the combustion characteristics of a dual-fuel (diesel-gas) engine at part loads, using a single-zone combustion model with detailed chemical kinetics for combustion of natural gas fuel. The authors have developed software in which the pilot fuel is considered as a subsidiary zone and a heat source derived from two superimposedWiebe combustion functions to account for its contribution to ignition of the gaseous fuel and the rest of the total released energy. The chemical kinetics mechanism consists of 112 reactions with 34 species. This quasi-two-zone combustion model is able to establish the development of the combustion process with time and the associated important operating parameters, such as pressure, temperature, heat release rate (HRR), and species concentration. Therefore, this paper describes an attempt to investigate the combustion phenomenon at part loads and using hot exhaust gas recirculation (EGR) to improve the above-mentioned drawbacks and problems. By employing this technique, it is found that lower percentages of EGR and allowance for its thermal and radical effects have a positive influence on performance and emission parameters of dual-fuel engines at part loads. Predicted values show good agreement with corresponding experimental values under special engine operating conditions (quarter-load, 1400 r/min). Implications are discussed in detail.

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Numerical Study of Combustion and Emission Characteristics of a Diesel/Methanol Dual Fuel (DMDF) Engine

Energy & Fuels ◽

10.1021/acs.energyfuels.5b00644 ◽

2015 ◽

Vol 29 (6) ◽

pp. 3963-3971 ◽

Cited By ~ 10

Author(s):

Ruzhen Zang ◽

Chunde Yao

Keyword(s):

Numerical Study ◽

Dual Fuel ◽

Emission Characteristics

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Effect of EGR on Combustion and Emission Characteristics of Marine Dual Fuel Engines

Proceedings of the 2017 International Conference on Computational Science and Engineering (ICCSE 2017) ◽

10.2991/iccse-17.2017.35 ◽

2017 ◽

Author(s):

Hongliang Yu ◽

Peng Sun ◽

Ji Wu ◽

Jinlong Bian

Keyword(s):

Dual Fuel ◽

Emission Characteristics ◽

Dual Fuel Engines

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A Multi-Dimensional CFD-Chemical Kinetics Approach in Detection and Reduction of Knocking Combustion in Diesel-Natural Gas Dual-Fuel Engines Using Local Heat Release Analysis

SAE International Journal of Engines ◽

10.4271/2013-01-0865 ◽

2013 ◽

Vol 6 (2) ◽

pp. 777-787 ◽

Cited By ~ 21

Author(s):

Amin Maghbouli ◽

Sina Shafee ◽

Rahim Khoshbakhti Saray ◽

Wenming Yang ◽

Vahid Hosseini ◽

...

Keyword(s):

Natural Gas ◽

Heat Release ◽

Chemical Kinetics ◽

Local Heat ◽

Dual Fuel ◽

Release Analysis ◽

Dual Fuel Engines

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Effects of Various Fuels on Combustion and Emission Characteristics of a Four-Stroke Dual-Fuel Marine Engine

Journal of Marine Science and Engineering ◽

10.3390/jmse9101072 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1072

Author(s):

Van Chien Pham ◽

Beom-Seok Rho ◽

Jun-Soo Kim ◽

Won-Ju Lee ◽

Jae-Hyuk Choi

Keyword(s):

Alternative Fuels ◽

Numerical Study ◽

Combustion Process ◽

Simulation Software ◽

Dual Fuel ◽

Injection Timing ◽

Emission Characteristics ◽

Marine Engine ◽

Adjustment Method ◽

Simulation Results

A numerical study was carried out to investigate the effects of methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), and dimethyl ether (DME) on the combustion and emission characteristics of a four-stroke gas-diesel dual-fuel (DF) marine engine at full load. Three-dimensional simulations of the combustion process and emission formation inside the engine cylinder in the diesel and DF modes were performed using the AVL FIRE R2018a simulation software to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results agreed well with the measured values reported in the engine shop test technical data. The simulation results showed reductions in the in-cylinder peak pressure and temperatures, as well as the emission formations, in the DF modes in comparison to the diesel mode. The DF mode could significantly reduce nitric oxide (NO) emissions (up to 96.225%) of DME compared to the diesel mode. Meanwhile, C3H8 and CH4 fuels effectively reduced the soot (up to 82.78%) and carbon dioxide (CO2) emissions (by 21.33%), respectively, compared to the diesel mode. However, the results also showed longer ignition delay times of the combustion processes when the engine operated in the DF mode, particularly in the DME-diesel mode. The combustion and emission characteristics of the engine were also analyzed when varying the injection timing; the results showed that applying the injection timing adjustment method could further address NO emission problems but led to a decrease in the engine power. Therefore, it is necessary to consider the benefits and disadvantages of adopting the injection timing adjustment strategy to address certain engine emission problems. This study successfully analyzed the benefits of using various gas fuels as alternative fuels and the injection timing adjustment method in DF marine engines to meet the International Maritime Organization (IMO) emission regulations without the use of any emission after-treatment devices.

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