Improvement of combustion and emissions in diesel engines by means of enhanced mixture formation based on flash boiling of mixed fuel

Senda, Jiro; Wada, Yoshimitsu; Kawano, Daisuke; Fujimoto, Hajime

doi:10.1243/14680874jer02007

Cited by 80 publications

(26 citation statements)

References 19 publications

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“…Several turbulence models those are available to predict the flow and cavitation behavior for our CFD problem in (11) And, Where, is the mean rate-of-rotation tensor viewed in a rotating reference frame with the angular velocity ω k . The model constants A 0 and A S are given by Where, (12) It is clear that, C μ is a function of the mean strain and rotation rates, the angular velocity of the system rotation, and the turbulence fields (k and ε). C μ may be shown to recover the standard value of 0.09 for an inertial sublayer in an equilibrium boundary layer.…”

Section: Turbulence Modeling Approachmentioning

confidence: 99%

“…First, if there is vapor along the wall, the liquid will have a slip condition boundary, thus allowing the velocity of the liquid to increase [9,10,11]. Second, cavitation inside the diesel injector nozzle leads to an increase of the spray cone angle which can improve the air fuel mixing process [12,13,14]. The fuel flow at the nozzle exit was characterized by measuring both the injection rate and the momentum flux for a wide range of typical rail and cylinder pressures experimentally.…”

Section: Introductionmentioning

confidence: 99%

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Computational Evaluation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector

Bastawissi

Elkelawy

2012

SAE Int. J. Engines

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The capabilities of various numerical models to accurately account for the onset and development of cavitation in diesel injector nozzles is assessed and evaluated. The numerical predictions of the models are computed, and are compared to measured experimental data and observations. The numerical predictions for actual diesel nozzle geometry have been validated with experimental measurements of the total vapor mass flow rate. This vapor flow is found to be developed along the nozzle length due to the nucleation of the cavitation bubbles inside the diesel injector. The cavitation inception criteria that is used for the quantitative cavitation calculations included vapor quality, voidage, cavitation kinetic energy and cavitation energy. The results indicate that the cavitation simulation model predicts a diffused and gradual vapor distribution inside the nozzle in agreement with the experimental data. The cavitation inception criteria used in current numerical modeling has matured to the level where it can usefully identify many of the characteristics of cavitation, and can significantly contribute to the optimization of cavitation production inside diesel injector. The calculations performed indicate that for the same model assumptions, such as the numerical implementation, discretization scheme and turbulence model, the predictions of the different cavitation sub-models are phenomenologically different. The calculations indicate that the Zwart-Gerber-Belamri model predicts a large void zone inside the injector delivery orifice and fail to capture the transition from incipient to fully developed cavitation, while the Singhal et al. model predicts a more diffused and gradual vapor distribution in agreement with the experimental model data. From the raw results, the values of the relevant parameters were computed, and the occurrence of cavitation was clearly identified. The results evidenced interesting differences in the permeability of the characteristics and strength of cavitation in nozzle under real diesel engine conditions.

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Section: Turbulence Modeling Approachmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Computational Evaluation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector

Bastawissi

Elkelawy

2012

SAE Int. J. Engines

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“…With improved atomization, gas turbine operations can realize improved emissions as compared with those that use conventional diesel. 20 Most atomization techniques, though with many merits, have shown inadequacies in fuel atomization in gas turbines. [21][22][23] This is due to relative increase in dynamic viscosity and surface tension.…”

Section: The Need For Novel Atomization Methodsmentioning

confidence: 99%

“…However, they have yet to be fully optimized for emissions; consequently, the probability of biodiesel to be a low emission alternative fuel option is still at the beginning and being evaluated. With improved atomization, gas turbine operations can realize improved emissions as compared with those that use conventional diesel …”

Section: Introductionmentioning

confidence: 99%

Fuel atomization in gas turbines: A review of novel technology

et al. 2019

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Summary The atomization of fuel is crucial in the combustion and emission of a gas turbine, and the fuel atomization is continuous without any cycles or strokes. However, to achieve a desired amount of combustion during this continuous process, fuel must be added and mixed with the high‐pressure air exiting the compressor in proper proportions. To make the engine as small and lightweight as possible is a constraint and requires the fuel injection, mixing, and combustion to occur within the smallest volume possible. In most cases, this is inefficient and less practicable. A major drawback is the requirement of high injection pressure with relatively small increase in flow rate. In recent years, research was conducted to improve fuel atomization in a gas turbine by using different novel approaches that were simpler, more adaptable, and efficient to enhance the atomization. However, most of these studies were in isolation without any comprehensive literature on recent trends. Therefore, this review attempts to give an insight on recent development of fuel atomization in a gas turbine. Particular emphasis was given to air‐, plasma‐, ultrasound‐, and supercritical fluid–assisted atomization techniques.

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“…To reach future emission standards, the fuel distribution in the combustion chamber and the droplet size distribution must be controlled appropriately. The different approaches to enhance the diesel fuel spray and reduce the diesel engine emissions while engine performance and soot formation remain almost constant have been used [1]- [3]. In which, the use of fuel additive to enhance the fuel mixture where a low boiling point fuel such as CO 2 , gas fuel, or gasoline is mixed with a higher boiling point fuel such as diesel gas oil.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Flow Pattern inside a Diesel Engine Injection Nozzle to Determine the Relationship between Various Flow Parameters and the Occurrence of Cavitation

Bastawissi¹,

Elkelawy²

2014

ENG

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In diesel engines the fuel injection system produces the spray, which directly affects the combustion of the fuel, which in turn determines the production of pollutants. In spite of this, the details of this causal relationship remain unclear. There is, however, a lack of quantitative experimental data for determining and visualizing the cavitation inside real size diesel injector nozzle. The present work is devoted to analyze analytically the flow pattern inside the nozzle of a diesel engine working with hydrocarbon fuel (Diesel fuel) and to predict the relationship between the various flow parameters and occurrence of fuel cavitation in such nozzles. Basic physical parameters affecting this phenomenon are identified and quantified while the effect of nozzle geometry, fuel injection pressure, and engine cylinder temperature upon the flow pattern and occurrence of cavitation in such nozzles are assessed. In this study, a commercial computational fluid dynamics (CFD) package (FLUENT-T grid) is used while a computational grid is generated for the real geometry of diesel injector nozzle using (ANSYS). The suitability of the generated computational grid to give reliable results is examined using the suitable procedures and techniques. The results indicated that, cavitation modeling has reached a stage of maturity and it can usefully identify many of the cavitation structures present in internal nozzle flows and their dependence on nozzle design and flow conditions. The qualitative distributions and comparison of cavitation inception and distribution as well as flow parameters at the nozzle exit are also studied.

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Improvement of combustion and emissions in diesel engines by means of enhanced mixture formation based on flash boiling of mixed fuel

Cited by 80 publications

References 19 publications

Computational Evaluation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector

Computational Evaluation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector

Fuel atomization in gas turbines: A review of novel technology

Investigation of the Flow Pattern inside a Diesel Engine Injection Nozzle to Determine the Relationship between Various Flow Parameters and the Occurrence of Cavitation

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