Modeling the Pilot Injection and the Ignition Process of a Dual Fuel Injector with Experimental Data from a Combustion Chamber Using Detailed Reaction Kinetics

Frühhaber, Jens; Peter, Andreas; Schuh, Sebastian; Lauer, Thomas; Wensing, Michael; Winter, Franz; Priesching, Peter; Pachler, K.G.R.

doi:10.4271/2018-01-1724

Cited by 10 publications

(15 citation statements)

References 17 publications

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“…The main challenge here is to describe the interaction of the two fuels during autoignition and turbulent combustion. In the case of autoignition the use of detailed reaction chemistry is able to correctly predict the ignition delay and the formation of the first flame structures, as shown by the authors in [8]. It further offers a deeper insight into the ongoing chemical processes during the autoignition of the pilot fuel, which several authors have investigated through spray simulations [9][10][11][12].…”

Section: Introductionmentioning

confidence: 88%

“…For this purpose, an ECFM model was adapted to consider the effect of natural gas on the ignition delay of the pilot fuel. The injection and the ignition of the pilot fuel have been investigated in detail in a previous study [8], which serves as a basis for the present work. The simulations were validated against experimental data from an engine test bench.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation of the Turbulent Flame Propagation in Dual Fuel Engines by Means of Large Eddy Simulation

Frühhaber

Lauer

2021

Energies

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Dual fuel combustion depicts a possible alternative to reduce emissions from large engines and is characterized by injecting a small amount of diesel fuel into a lean natural gas–air mixture. Thereby, the presence of autoignition, diffusive and premixed combustion determine the high complexity of this process. In this work, an Extended Coherent Flame Model was adapted to consider the effect of natural gas on the ignition delay time. This model was afterward utilized to simulate 25 consecutive engine cycles employing LES. In this framework, the ensemble-average flow field was compared to a RANS solution to assess the advantages of LES in terms of the prediction of the in-cylinder flow field. A detailed investigation of the heat release characteristic showed that natural gas already highly contributes to the heat release at the beginning of combustion. Furthermore, a methodology to investigate the turbulent combustion regimes was utilized. It could be ascertained that the combustion mainly occurs in the regime of thin reaction zones. Possible triggers of cycle-to-cycle variations were determined in the velocity fluctuations in the cylinder axis direction and the flame formation in the gaps between the spray plume. The findings support the understanding of dual fuel combustion and serve as a basis for developing future combustion models.

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Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Turbulent Flame Propagation in Dual Fuel Engines by Means of Large Eddy Simulation

Frühhaber

Lauer

2021

Energies

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“…This was necessary to depict the experimentally observed spray propagation in the ballistic working regime of the injector, which is common for dual fuel operation with small diesel amounts. For further details concerning the experimental setup and the spray modeling refer to Reference [8]. The ignition of the pilot fuel is simulated using the general gas phase reactions module available in AVL FIRE TM .…”

Section: Investigation Of Inhomogeneous Fuel Mixturesmentioning

confidence: 99%

“…The refinements in the spray area are transferred from the spray box investigations, to ensure a comparable mixture preparation. For further information on the experimental setup and the computational method refer to Reference [8]. The simulations of the dual fuel combustion were carried out with an energetic diesel share of 5%, 20% and 40%, whereby, for illustration, in the following consideration results with 20% share are discussed in detail.…”

Section: Investigation Of Inhomogeneous Fuel Mixturesmentioning

confidence: 99%

“…The data needed for the evaluation were measured with a rapid compression machine (RCM) and a shock tube (ST) [6,7]. The IDT calculation of inhomogeneous mixtures was performed with the software AVL FIRE TM (Version 2018.1, AVL List GmbH, Graz, Austria), whereby the experimental comparative data were measured with a rapid compression expansion machine (RCEM) and a combustion vessel [8].…”

Section: Introductionmentioning

confidence: 99%

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A Novel Dual Fuel Reaction Mechanism for Ignition in Natural Gas–Diesel Combustion

et al. 2019

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In this study, a reaction mechanism is presented that is optimized for the simulation of the dual fuel combustion process using n-heptane and a mixture of methane/propane as surrogate fuels for diesel and natural gas, respectively. By comparing the measured and calculated ignition delay times (IDTs) of different homogeneous methane–propane–n-heptane mixtures, six different n-heptane mechanisms were investigated and evaluated. The selected mechanism was used for computational fluid dynamics (CFD) simulations to calculate the ignition of a diesel spray injected into air and a natural gas–air mixture. The observed deviations between the simulation results and the measurements performed with a rapid compression expansion machine (RCEM) and a combustion vessel motivated the adaptation of the mechanism by adjusting the Arrhenius parameters of individual reactions. For the identification of the reactions suitable for the mechanism adaption, sensitivity and flow analyzes were performed. The adjusted mechanism is able to describe ignition phenomena in the context of natural gas–diesel, i.e., dual fuel combustion.

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Numerical study of novel OME1−6 combustion mechanism and spray combustion at changed ambient environments

Wiesmann,

Qiu,

Han

et al. 2024

Front. Energy

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For a climate-neutral future mobility, the so-called e-fuels can play an essential part. Especially, oxygenated e-fuels containing oxygen in their chemical formula have the additional potential to burn with significantly lower soot levels. In particular, polyoxymethylene dimethyl ethers or oxymethylene ethers (PODEs or OMEs) do not contain carbon-carbon bonds, prohibiting the production of soot precursors like acetylene (C2H2). These properties make OMEs a highly interesting candidate for future climate-neutral compression-ignition engines. However, to fully leverage their potential, the auto-ignition process, flame propagation, and mixing regimes of the combustion need to be understood. To achieve this, efficient oxidation mechanisms suitable for computational fluid dynamics (CFD) calculations must be developed and validated. The present work aims to highlight the improvements made by developing an adapted oxidation mechanism for OME1−6 and introducing it into a validated spray combustion CFD model for OMEs. The simulations were conducted for single- and multi-injection patterns, changing ambient temperatures, and oxygen contents. The results were validated against high-pressure and high-temperature constant-pressure chamber experiments. OH*-chemiluminescence measurements accomplished the characterization of the auto-ignition process. Both experiments and simulations were conducted for two different injectors. Significant improvements concerning the prediction of the ignition delay time were accomplished while also retaining an excellent agreement for the flame lift-off length. The spatial zones of high-temperature reaction activity were also affected by the adaption of the reaction kinetics. They showed a greater tendency to form OH* radicals within the center of the spray in accordance with the experiments.

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Modeling the Pilot Injection and the Ignition Process of a Dual Fuel Injector with Experimental Data from a Combustion Chamber Using Detailed Reaction Kinetics

Cited by 10 publications

References 17 publications

Numerical Investigation of the Turbulent Flame Propagation in Dual Fuel Engines by Means of Large Eddy Simulation

Numerical Investigation of the Turbulent Flame Propagation in Dual Fuel Engines by Means of Large Eddy Simulation

A Novel Dual Fuel Reaction Mechanism for Ignition in Natural Gas–Diesel Combustion

Numerical study of novel OME1−6 combustion mechanism and spray combustion at changed ambient environments

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