A Preliminary Model for the Formation of Nitric Oxide in Direct Injection Diesel Engines and Its Application in Parametric Studies

Shahed, S. M.; Chiu, W. S.; Yumlu, V. S.

doi:10.4271/730083

Cited by 37 publications

(4 citation statements)

References 16 publications

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“…Only With respect to the physical formulation, published phenomenological NOx models for DI diesel engines either only consider the products of diffusion combustion 33,47 for computing NOx formation and decomposition or do not distinguish in the physical treatment between the products of premixed and diffusion combustion. 30,37,38,48 This approach has generally been proven to provide good results since first, in conventional diesel combustion usually most of the fuel is oxidized in the diffusion-controlled combustion phase (operating conditions with short IDs and/or pilot injection), and second, experimental studies have shown that under such conditions, the reactants of premixed burn are too rich to form NOx. 49,50 Moreover, local in-cylinder laser-induced fluorescence measurements 51,52 showed that NOx formation is negligible prior to the onset of the diffusion combustion phase for conventional diesel combustion (conventional diesel combustion is characterized by short ID relative to the injection duration and by high NOx and soot emissions.…”

Section: Survey On Nox Modellingmentioning

confidence: 99%

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NOx emissions in direct injection diesel engines – part 1: Development of a phenomenological NOx model using experiments and three-dimensional computational fluid dynamics

Brückner

Pandurangi

Kyrtatos

et al. 2017

International Journal of Engine Research

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There exists a well-established correlation of exhaust NOx emissions arising from diesel engines with the adiabatic flame temperature, in particular for conventional (i.e. short ignition delay, diffusion combustion-dominated) operating conditions. Most published NOx emission models rely on this correlation. However, numerous experimental studies have identified operating conditions where this correlation fails to capture the exhaust NOx trend. In this work, a novel phenomenological NOx model concept is introduced, including a first successful validation against experimental data. The model development is based on experimental observations and is supported by three-dimensional computational fluid dynamics computations, strengthening the understanding of the underlying mechanisms leading to the discrepancy between the adiabatic flame temperature and exhaust NOx trend. For long ignition delay operating conditions, the improved mixture preparation before ignition leads to reduced mixing rates during and after combustion. Both the improved mixture preparation before ignition and the instantaneous increase of mass observed above 2000 K after start of combustion are due to compression heating of the burned gases. Key features of the model are improved description of mixture distribution at start of combustion, NOx formed in products of premixed burn, different physical treatments of premixed and diffusion sourced products, and inherent consideration of burned gas compression heating. Model results capture the NOx emissions for conventional diesel combustion, as well as for operating conditions where the NOx emissions do not follow the adiabatic flame temperature trend. Moreover, the results show that the contribution of NOx from products from premixed burn and the consideration of compression heating effects on burned (postflame) gases are essential to capture the NOx emissions under the latter conditions.

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Section: Survey On Nox Modellingmentioning

confidence: 99%

“…The first promising approaches for computing NOx emissions for diesel engines were introduced in the 1970s by Shahed et al, 30 Khan et al, 31 Hiroyasu and Kadota, 32 and Murayama et al, 33 establishing a general framework that is widely accepted. This framework is composed of the following key components.…”

Section: New Insights Into the Nox Trend-reversalmentioning

confidence: 99%

NOx emissions in direct injection diesel engines – part 1: Development of a phenomenological NOx model using experiments and three-dimensional computational fluid dynamics

Brückner

Pandurangi

Kyrtatos

et al. 2017

International Journal of Engine Research

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“…Phenomenological modeling has been used to describe DI/CI combustion in a number of instances, ranging from early work by Hiroyasu and Kadota to more recent efforts using the Cummins engine model by Shahed and co-workers. [18][19][20][21][22] These other efforts tend to focus on fuel vaporization and mixing to establish mixture profiles but don't represent entrainment through a flame sheet as was identified by Dec in his conceptual model. One modeling approach that did focus on this particular attribute was developed by Broadwell and Lutz and is called the Two-Stage Lagrangian (TSL) model.…”

Section: Introductionmentioning

confidence: 99%

A transient and spatially confined phenomenological combustion model for direct-injection, compression-ignition engines in fuel-rich applications: N-Stage Lagrangian (NSL)

Donohue¹,

Cetin²,

Edwards

2022

International Journal of Engine Research

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Previous efforts aimed at increasing the efficiencies of systems where a piston engine serves as a primary work producer have led to interest in operating direct-injection, compression-ignition (DI/CI) engines at overall stoichiometric or fuel-rich equivalence ratios. In order to extend the current understanding of DI/CI combustion to applications in this regime, a phenomenological model is proposed. The model builds on previous conceptual and phenomenological models that describe steady, reacting free jets and applies the underlying concepts to a spatially confined, transient system. The model is assessed in its ability to describe and interpret experimental data through comparisons to experimental data collected in this regime, with a particular focus on its ability to address the observed trends in exhaust gas species concentrations. Through this comparison to experimental data, potential insights provided by the model are discussed.

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“…The engine community subsequently developed chemically kinetic and mixing controlled combustion models Way, 1970, 1971), bulk mixing rate submodels (Grigg and Syed, 1970;Khan et al, 1971), and thermodynamic multi-zone models (Bastress et al, 1971;Shahed et al, 1973Shahed et al, , 1975Hodgetts and Shroff, 1975;Chiu et al, 1976;Hiroyasu and Kadota, 1976;Maguerdichian and Watson, 1978). These efforts were fundamental in establishing the basis for today's multizone and bulk mixing combustion models that have been fine tuned throughout the last twenty-five years through careful development of air-fuel mixing submodels (Dent and Mehta, 1981;Dent et al, 1982, Kono et al, 1985Kyriakides et al, 1986;Schihl et al, 1996) and more comprehensive multi-zone models (Hiroyasu et al, 1983;Lipkea and DeJoode, 1987;Kouremenos et al, 1986Kouremenos et al, , 1987Kouremenos et al, , 1997Bazari, 1992;Li and Assanis, 1993;Mehta et al 1995;Jung and Assanis, 2001).…”

Section: Introductionmentioning

confidence: 99%

Determination of Laminar Flame Speed of Diesel Fuel for Use in a Turbulent Flame Spread Premixed Combustion Model

Schihl¹,

Tasdemir²,

Bryzik³

2006

Transformational Science and Technology for the Current and Future Force

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One of the key challenges facing diesel engine system modelers lies in adequately predicting the fuel burning rate profile given the direct relationship between energy release and key performance parameters such as fuel economy, torque, and exhaust emissions. Current state-of-the-art combustion sub-models employed in such system simulation codes rely heavily on empiricism and successful application of such sub-models for new engine designs is highly dependent on past experience with similar combustion systems. One common approach to address this issue is to expend great effort choosing associated empirical coefficients over a range of similar combustion system designs thus improving the potential predictive capability of a given empirical model. But, continual combustion system development and design changes limit the extrapolation and application of such generic combustion system dependent coefficients to new designs due to various reasons including advancements in fuel injection systems, engine control strategy encompassing multiple injections, and combustion chamber geometry.In order to address these very difficult challenges, an extensive effort has been applied toward developing a physically based, simplified combustion model for military-relevant diesel engines known as the Large Scale Combustion Model (LSCM). Recent effort has been spent further refining the first stage of the LSCM two stage combustion model that is known as the premixed phase sub-model. This particular sub-model has been compared with high-speed cylinder pressure data acquired from two relevant direct injection diesel engines with much success based on a user defined parameter referred to as the laminar flame speed by the combustion community. It is a physically significant parameter that is highly dependent on local temperature, pressure, and oxygen concentration but little experimental effort has been spent determining its behavior for diesel fuel due to ignition constraints. This submission will discuss one approach of indirectly determining this key combustion parameter.

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A Preliminary Model for the Formation of Nitric Oxide in Direct Injection Diesel Engines and Its Application in Parametric Studies

Cited by 37 publications

References 16 publications

NOx emissions in direct injection diesel engines – part 1: Development of a phenomenological NOx model using experiments and three-dimensional computational fluid dynamics

NOx emissions in direct injection diesel engines – part 1: Development of a phenomenological NOx model using experiments and three-dimensional computational fluid dynamics

A transient and spatially confined phenomenological combustion model for direct-injection, compression-ignition engines in fuel-rich applications: N-Stage Lagrangian (NSL)

Determination of Laminar Flame Speed of Diesel Fuel for Use in a Turbulent Flame Spread Premixed Combustion Model

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