Predicting Ignition and Combustion of a Pilot Ignited Natural Gas Jet Using Numerical Simulation Based on Detailed Chemistry

Jud, Michael; Fink, Georg; Sattelmayer, Thomas

doi:10.1115/icef2017-3533

Cited by 6 publications

(3 citation statements)

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“…8 that the burning region can be clearly distinguished from the unburning region. According to a previous study [63], the initial combustion stage of the HPDI engine belongs to the premixed combustion, which can be demonstrated In summary, the 35-step mechanism can reproduce the ignition delay times of n-heptane at all research temperatures, while the 27-step mechanism gives reasonable predictions of ignition delay times for n-heptane at high temperatures. Both of these two mechanisms give well predictions of ignition delay times for methane.…”

Section: Mechanism Validation In a Marine Enginesupporting

confidence: 55%

Development of a simplified n-heptane/methane model for high-pressure direct-injection natural gas marine engines

Liu

et al. 2021

Front. Energy

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High-pressure direct-injection (HPDI) of natural gas is one of the most promising solutions for the future ship engines, for which the combustion process is mainly controlled by the chemical kinetics. However, the employment of detail chemical mechanisms for the multi-dimensional combustion simulation is significantly expensive due to the large scale of the marine engine. In the present study, a reduced n-heptane/methane mechanism consisted of 35-step reactions was constructed using multiple reduction approaches. Then this mechanism was further reduced to include only 27 reactions by the HyChem (Hybrid Chemistry) method. An overall good agreement with the experimentally measured ignition delay data of both nheptane and methane for these two reduced mechanisms was achieved and reasonable predictions for the measured laminar flame speeds were obtained for the 35-step mechanism. But the 27-step mechanism cannot predict the laminar flame speed very well. In addition, these two reduced mechanisms were both able to reproduce the experimentally measured in-cylinder pressure and heat release rate profiles for a HPDI natural gas marine engine, although the engine-out CO emission was overpredicted and the NOx emission was slightly underestimated. The predicted distributions of temperature and equivalence ratio by the 35-step and 27-step mechanisms are similar with those of the 334-step mechanism. However, the predicted distributions of OH and CH2O are significantly different from those of the 334-step mechanism. In short, the developed reduced chemical kinetic mechanisms provide a high-efficient and dependable method to simulate the characteristics of combustion and emissions in HPDI natural gas marine engines.

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Section: Mechanism Validation In a Marine Enginesupporting

confidence: 55%

Development of a simplified n-heptane/methane model for high-pressure direct-injection natural gas marine engines

Liu

et al. 2021

Front. Energy

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“…The combustion is calculated using the SAGE Detailed Chemical Kinetics Solver with reaction mechanism resulting from a combination of the GRI3.0 33 for methane and the Chalmers53 n-heptane mechanisms. The Chalmers 53 has been giving good results for methane-diesel HPDF in 34,35 and the GRI3.0 is validated in literature – giving satisfying results for the laminar burning velocity in ammonia combustion. 10,36…”

Section: Methodsmentioning

confidence: 76%

Investigation of ammonia and hydrogen as CO2-free fuels for heavy duty engines using a high pressure dual fuel combustion process

Frankl

Gleis

Karmann

et al. 2020

International Journal of Engine Research

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This work is a numerical study of the use of ammonia and hydrogen in a high-pressure-dual-fuel (HPDF) combustion. The main fuels (hydrogen and ammonia) are direct injected and ignited by a small amount of direct injected pilot fuel. The fuels are injected using a dual fuel injector from Woodward L’Orange, which can induce two fuels independently at high pressures up to 1800 bar for the pilot fuel and maximum 500 bar for the main. The numerical CFD-model gets validated for of hydrogen-HPDF with experimental data. Due to safety issues at the test rig it was not possible to use ammonia in the experiments, so it is modelled using the numerical model. It is assumed that the CFD-model also gives qualitative correct results for the use of ammonia as main fuel, so a parameter study of ammonia-HPDF is made. The results for the hydrogen-HPDF show, that hydrogen can be used in the engine without any further modifications. The combustion is very stable, and the hydrogen ignites almost immediately when it enters the combustion chamber. The results of the ammonia combustion indicate, that the HPDF combustion mode can handle ammonia effectively. It seems beneficial to inject the ammonia at higher pressures than hydrogen. Also pre-heating the ammonia can increase the combustion efficiency.

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“…They found that a strong interaction between diesel spray and natural gas jet led to the delayed pilot ignition but the rapid and stable onset of the gas jet combustion process. By employing both the optical diagnostics and numerical modeling, Jud et al 26 investigated the ignition and combustion of a pilot ignited NG combustion process on a rapid compression machine. They found that an early NG start of ignition (SOI) timing results in a premixed-combustion process at the initial combustion stage.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Combustion Kinetics Process in a High-Pressure Direct Injection Natural Gas Marine Engine

Liu

et al. 2021

Energy Fuels

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The detailed combustion kinetic processes of a high-pressure direct injection (HPDI) natural gas (NG) marine engine was investigated in the present work. A postprocessing code was employed to visualize the characteristic reactions that determine the combustion process. To evaluate the effect of mixture stratification on the combustion process, various NG injection timings were employed and four representative combustion periods were selected, including the timings when 1% (CA1), 5% (CA5), 10% (CA10), and 50% (CA50) of the total fuel energy are released. A higher heat release rate (HRR) was generated with a more advanced NG start of injection (SOI) timing, which, however, had limited effects on the main representative exothermic reactions (REXRs) within the high heat release (HHR) region and the dominant formation reactions of CH 2 O and OH, which are known as the indicators of low heat release (LHR) and HHR, respectively. Besides, for different NG SOI timing simulation, the consumption of CH 4 was all dominated by reactions H + CH 4 = CH 3 + H 2 and OH + CH 4 = CH 3 + H 2 O and the dominated REXR of the LHR region was reaction CH 3 + O 2 = CH 3 O 2 . Furthermore, with an advanced NG injection timing, significant changes were observed for the reaction paths of CH 2 , CH 2 O, and HCO from the premixed-combustion phase (CA10) to the mixing-controlled combustion phase (CA50). The results of the present study are able to provide a theoretical fundamental for the practical control of the HPDI NG marine engine.

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Predicting Ignition and Combustion of a Pilot Ignited Natural Gas Jet Using Numerical Simulation Based on Detailed Chemistry

Cited by 6 publications

References 0 publications

Development of a simplified n-heptane/methane model for high-pressure direct-injection natural gas marine engines

Development of a simplified n-heptane/methane model for high-pressure direct-injection natural gas marine engines

Investigation of ammonia and hydrogen as CO2-free fuels for heavy duty engines using a high pressure dual fuel combustion process

Investigation of the Combustion Kinetics Process in a High-Pressure Direct Injection Natural Gas Marine Engine

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