Numerical analysis for optimizing combustion strategy in an ammonia-diesel dual-fuel engine

Shin, Jisoo; Park, Sungwook

doi:10.1016/j.enconman.2023.116980

Cited by 83 publications

(8 citation statements)

References 33 publications

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“…Bond-order-dependent characterization is achieved by detailed parameterization of the atomic, bonding, angular, and torsional properties of each particle, and the interactions within the system [38]. The total energy of the system can be calculated by summing all partial energy terms as described in R1: E system = E bond + E over + E under + E val + E pen + E tors + E conj + E vdWaals + E coulomb (1) where E bond , E over , E under , E val , E pen , E tors , and E conj correspond to bond energy, overcoordination energy, under-coordination energy, bond angle energy, compensation energy, torsion energy, and four-body conjugation energy. The non-bonding terms mainly consist of van der Waals force energy (E vdWaals ) and Coulomb force energy (E coulomb ).…”

Section: Reactive Force-field Molecular Dynamics (Reaxff Md)mentioning

confidence: 99%

“…Currently, the global transportation industry relies mainly on fossil energy sources [1], but the combustion of these traditional fossil energy sources causes a lot of pollution. To fundamentally solve this problem, finding clean energy sources that can replace traditional energy sources has become one of the most important research topics [2,3].…”

Section: Introductionmentioning

confidence: 99%

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Reactive Molecular Dynamics Study of Pollutant Formation Mechanism in Hydrogen/Ammonia/Methanol Ternary Carbon-Neutral Fuel Blend Combustion

Sun,

Liu,

Wang

et al. 2023

Molecules

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Hydrogen, ammonia, and methanol are typical carbon-neutral fuels. Combustion characteristics and pollutant formation problems can be significantly improved by their blending. In this paper, reactive molecular dynamics were used to investigate the pollutant formation characteristics of hydrogen/ammonia/methanol blended fuel combustion and to analyze the mechanisms of CO, CO2, and NOX formation at different temperatures and blending ratios. It was found that heating can significantly increase blending and combustion efficiency, leading to more active oxidizing groups and thus inhibiting N2 production. Blended combustion pollutant formation was affected by coupling effects. NH3 depressed the rate of CO production when CH4O was greater than 30%, but the amount of CO and CO2 was mainly determined by CH4O. This is because CH4O provides more OH, H, and carbon atoms for CO and CO2 to collide efficiently. CH4O facilitates the combustion of NH3 by simplifying the reaction pathway, making it easier to form NOX.

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Section: Reactive Force-field Molecular Dynamics (Reaxff Md)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reactive Molecular Dynamics Study of Pollutant Formation Mechanism in Hydrogen/Ammonia/Methanol Ternary Carbon-Neutral Fuel Blend Combustion

Sun,

Liu,

Wang

et al. 2023

Molecules

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“…Another simulated work by Jin et al 26 showed that an ITE of 49.8% was achieved at a 50% ammonia ratio by injection timing optimization. Shin and Park 27 found that an advanced injection timing could compensate for the effect of slow flame propagation of ammonia and achieved shortened combustion duration and reduced NH 3 and N 2 O emissions. These studies have demonstrated the significance of the injection timing and energy ratio in improving ammonia combustion and emissions.…”

Section: Introductionmentioning

confidence: 99%

Effects of Injection Timings and Energy Ratios on the Combustion and Emission Characteristics of n-Heptane/Ammonia RCCI Mode

Zhang,

Chen,

et al. 2024

Energy Fuels

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Blending with a high-reactivity fuel is recognized as an effective way to overcome poor combustion and heavy emissions of ammonia (NH 3 ). In this study, we investigated the combustion performance and nitrogen-based emissions of an nheptane/ammonia blend in an optical engine operating under reactivity-controlled compression ignition (RCCI) mode, addressing the n-heptane energy ratio and injection timing. Considering the long ignition delay time of pure ammonia, the n-heptane energy ratio was selected as 20−40%, and the injection timings were selected as −70 to −35 °CA aTDC. The results demonstrate the substantial impact of both variables on engine performance. Notably, a critical injection timing (SOI = −50 °CA aTDC) was identified, exhibiting optimal combustion stabilities, while an increased n-heptane energy ratio facilitated the expansion of the stable operating conditions and increased the indicated mean effective pressure by up to 6.4%. Combustion visualization showed a transition in combustion mode from flame propagation to sequential autoignition with the advancement of injection timing, resulting in a more homogeneous combustion. Meanwhile, optimal flame development was observed at the critical injection timing. As the heptane fraction decreased, autoignition timing was obviously retarded and flame development depended on the local temperature field, suggesting the potential for the modulation of combustion mode through controlling the injection timing and energy ratio. Regarding nitrogen-based emissions, an advanced injection timing correlated with more homogeneous combustion, leading to a decrease of NH 3 by up to 47.7% and an increase of NO and NO 2 by approximately up to 65.9 and 22.4%, respectively. As the n-heptane energy ratio decreased, unburned NH 3 emissions increased by up to 40.4%, while NO 2 emissions decreased by up to 11.2%. NO emissions exhibited an initial increase followed by a subsequent decrease, and the maximum value reached 2698 ppm at the n-heptane energy ratio of 30%. N 2 O emissions displayed negative correlations with the autoignition timing and flame propagation speed, consistent with the observed variations in combustion stabilities.

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“…Furthermore, the level of unburned ammonia was reduced by 58.4%, indicating a significant enhancement over premixed ammonia combustion. The same authors implemented a similar study [27] to explore diesel injection timing alone, considering ammonia energy fractions from 40% to 90%. Advancing injection timing showed up to 11% more efficient combustion compared with diesel operation, although nitrogen oxide emissions increased with increasing ammonia energy fraction and advancing injection timing.…”

Section: Introductionmentioning

confidence: 99%

Computational Investigation of the Influence of Combustion Chamber Characteristics on a Heavy-Duty Ammonia Diesel Dual Fuel Engine

Sehili,

Loubar,

Tarabet

et al. 2024

Energies

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In response to increasingly stringent emissions regulations and the depletion of conventional fuel sources, integrating carbon-free fuels into the transport sector has become imperative. While hydrogen (H2) presents significant technical challenges, ammonia (NH3) could present a better alternative offering ease of transport, storage, and distribution, with both ecological and economic advantages. However, ammonia substitution leads to high emissions of unburned NH3, particularly at high loads. Combustion chamber retrofitting has proven to be an effective approach to remedy this problem. In order to overcome the problems associated with the difficult combustion of ammonia in engines, this study aims to investigate the effect of the piston bowl shape of an ammonia/diesel dual fuel engine on the combustion process. The primary objective is to determine the optimal configuration that offers superior engine performance under high load conditions and with high ammonia rates. In this study, a multi-objective optimization approach is used to control the creation of geometries and the swirl rate under the CONVERGETM 3.1 code. To maximize indicated thermal efficiency and demonstrate the influence of hydrogen enrichment on ammonia combustion in ammonia/diesel dual fuel engines, a synergistic approach incorporating hydrogen enrichment of the primary fuel was implemented. Notably, the optimum configuration, featuring an 85% energy contribution from ammonia, outperforms others in terms of combustion efficiency and pollutant reduction. It achieves over 43% reduction in unburned NH3 emissions and a substantial 31% improvement in indicated thermal efficiency.

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Numerical analysis for optimizing combustion strategy in an ammonia-diesel dual-fuel engine

Cited by 83 publications

References 33 publications

Reactive Molecular Dynamics Study of Pollutant Formation Mechanism in Hydrogen/Ammonia/Methanol Ternary Carbon-Neutral Fuel Blend Combustion

Reactive Molecular Dynamics Study of Pollutant Formation Mechanism in Hydrogen/Ammonia/Methanol Ternary Carbon-Neutral Fuel Blend Combustion

Effects of Injection Timings and Energy Ratios on the Combustion and Emission Characteristics of n-Heptane/Ammonia RCCI Mode

Computational Investigation of the Influence of Combustion Chamber Characteristics on a Heavy-Duty Ammonia Diesel Dual Fuel Engine

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