Modeling Diesel Spray Flame Liftoff, Sooting Tendency, and NOx Emissions Using Detailed Chemistry With Phenomenological Soot Model

Kong, Song‐Charng; Sun, Yong; Rietz, Rolf D.

doi:10.1115/1.2181596

Cited by 196 publications

(77 citation statements)

References 18 publications

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“…76 Research has shown that the composition and morphology of soot/particulate matter emissions from LTC strategies can vary widely, [78][79][80][81] and it has also been shown that the two-step soot model requires significant tuning to achieve predictions over a range of combustion modes. 82 Therefore, in this study, the qualitative sooting tendency of a given combustion strategy will be discussed using local equivalence ratio versus local temperature diagrams, like the one shown in Figure 1.…”

Section: Multi-dimensional Cfd Engine Modelingmentioning

confidence: 99%

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Dempsey

Curran

Wagner

2016

International Journal of Engine Research

136

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Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasoline has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this study, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities and challenges associated with the various fuel stratification levels.

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Section: Multi-dimensional Cfd Engine Modelingmentioning

confidence: 99%

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Dempsey

Curran

Wagner

2016

International Journal of Engine Research

136

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“…The third CFD results in the iteration were compared with the experimental results. Although a Primary Reference Fuel (PFR) blend of 71% (by volume) n-heptane and 29% (by volume) iso-octane, or PFR29, was used in the experiment, 100% n-heptane chemical reaction kinetics and fuel properties were used in the model prediction due to the availability of a chemistry mechanism (11) .…”

Section: Resultsmentioning

confidence: 99%

“…For the prediction of the temperature distribution of the engine components, such as the piston, liner, and cylinder head, a finite element Heat Conduction in Components (HCC) code (5) was used. (6) GASJET model (7) Radiation Discrete Ordinates Method (DOM) (8) Soot Refractive index m = n -κ i =1.8-1.0 i (9) Hot gas wide-band gray approximation (10) Combustion Detailed chemistry mechanism (11) Improved n-heptane reaction mechanism (12) Soot formation Two-step model (11) NO x Improved reduced 19-step model (13) Turbulence RNG k-ε Wall temperature Heat Conduction in Components code (5) The Discrete Ordinates Method (DOM) solves the Radiation Transfer Equation (RTE) for the intensity of radiation in a set of ordinates, each weighted by the solid angle subtended by that ordinate. The RTE and its boundary conditions are (14,8) …”

Section: Numerical Modelsmentioning

confidence: 99%

Effect of Radiation on Diesel Engine Combustion and Heat Transfer

Yoshikawa

Reitz

2009

JTST

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An investigation of the effect of radiation on NO x emission was conducted for low temperature diesel engine combustion by using advanced numerical models in a Computational Fluid Dynamics code. The Discrete Ordinates Method (DOM) model was used for the prediction of radiation, which is mainly radiated from soot emissions. The advanced numerical model was able to predict the pressure and heat release rate for a wide range of Start Of Injection (SOI) timing cases. It was found that the influence of the radiation was larger on soot formation than on NO x formation. However, the influence of the radiation on the emissions was smaller than the influence of the wall temperature on emissions. The reaction-induced interaction between NO x and soot emissions was found to be very small, only up to 2.5 % difference of engine-out NO x concentration.

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“…For spark-ignition engines, knock occurrence, which limits the compression ratio and therefore the efficiency at which a spark-ignition can operate, has been investigated with the use of numerical modeling and chemical models [Liang, L., Reitz, R., Iyer, C., and Yi, 2007;Linse, Kleemann, & Hasse, 2014]. The relationship of soot and nitrogen oxide (NOx) formation with various conditions within a diesel engine such as temperature, pressure and flame lift-off length, as well as design parameters such as spray nozzle geometry has also been explored using chemical kinetics [Kong, Sun, & Rietz, 2007;Som, Ramirez, Longman, & Aggarwal, 2011]. There exist numerous other studies in the literature that utilized chemical kinetic models to predict engine performance.…”

Section: Applicationsmentioning

confidence: 99%

Application of a multi-zone model for the prediction of species concentrations in rapid compression machine experiments

Wilson

Allen

2016

Combustion and Flame

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Accurate chemical kinetic models, which predict species evolution and heat release rates in chemically reactive systems, are essential for further advancements in fuel and combustion technology. An experimental facility that is widely used for evaluating the accuracy of kinetic models is a rapid compression machine (RCM), which creates a well-defined reaction environment by compressing a reactive mixture inside a chamber. Generally, RCM experiments are conducted in order to obtain ignition delay data. However, chemical speciation data provides greater insight into reaction pathways, and is therefore a more rigorous benchmark for validating kinetic models.In order for a chemical kinetic model to be evaluated using RCM data, the kinetic model must be coupled with a thermodynamic model that can predict the temporally varying conditions that evolve during an RCM experiment. The most common approach is to utilize a thermally and compositionally homogeneous 0-dimensional reactor model (HRM), which predicts conditions inside the hot core region of the main combustion chamber of an RCM, where a significant portion of the chemical reaction in an RCM takes place. This approach requires an effective volume profile, which is derived from the pressure profile of either a non-reactive experiment with similar transport properties as the condition of interest, or a separate multi-zone model (MZM), via the relationship between pressure and volume for an isentropic process. While HRMs have been shown to yield adequate ignition delay predictions, they cannot be used to predict average speciation data, since the conditions in the core region vary considerably from the average conditions of the total reaction chamber.This work introduces a modified MZM, which simulates chemical reaction throughout the entire temperature-varying main combustion chamber of an RCM, in addition to boundary work, conduction, and crevice flows as the traditional MZM approach. Simulating chemistry in the MZM allows for average speciation predictions, and eliminates the need for an HRM. The new approach is shown to yield similar average speciation data as CFD simulations (within 15% difference) for the combustion of primary reference fuels at various conditions. iii ACKNOWLEDGEMENTS

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Modeling Diesel Spray Flame Liftoff, Sooting Tendency, and NOx Emissions Using Detailed Chemistry With Phenomenological Soot Model

Cited by 196 publications

References 18 publications

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Effect of Radiation on Diesel Engine Combustion and Heat Transfer

Application of a multi-zone model for the prediction of species concentrations in rapid compression machine experiments

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