A Numerical Study of Multiple Fuel Injection Strategies for NO<sub>x</sub>Reduction from DI Diesel Engines

Wang, D.; Zhang, C.; Wang, Y.

doi:10.1080/15435070701465912

Cited by 22 publications

(7 citation statements)

References 18 publications

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“…Cavitation conditions, the liquid-vapor mass transfer evaporation and condensation is governed by the vapor transport equation 13where α is the vapor volume fraction, v denotes the vapor phase, and R e -R c represents the mass transfer source terms connected to the growth and collapse of the vapor bubbles respectively. (13) In the cavitation model it is assumed that there are sufficient nuclei for the inception of cavitation. Thus, the primary focus is on proper accounting of bubble growth and collapse.…”

Section: Cavitation Modelmentioning

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: Cavitation Modelmentioning

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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“…The variation of isentropic bulk modulus has direct effect on biodiesel's ignition timing (that are more appropriate in conditions of ultrasonic irradiation to diesel fuel one). Further, from this reason, the peak combustion temperature in the NO x formation interval is decrease, because the premixed combustion intensity is reduced (Wang et al 2007).…”

Section: Resultsmentioning

confidence: 99%

Attempts to Reduce Biodiesel Blends Nox Pollutant Emissions by Ultrasonic Conditioning

Mariașiu

2014

Transport

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The conditions imposed by the renewable energy Directive 2009/28/EC make it mandatory for EU member countries to ensure that by 2020 fossil fuels used in the transport sector contain a 10% component of biofuel. The 10% limit is based on results of experiments conducted by engine manufacturers and researchers in the biofuels domain, which show that this percentage can be used in IC engines without major technical changes to equipment and engine systems. Taking into account that increasing the percentage of biodiesel in blends results in significant reductions of CO2 emissions, an immediate way to surpass the 10% limit is to carry out external and/or internal processes that will act on the physico-chemical properties of those biofuels. This paper presents data and results from experiments examining the process of ultrasonic irradiation of rapeseed oil methyl ester type biodiesel. The results show the effects of the irradiation process on biodiesel physical parameters such as density, kinematic viscosity, speed of sound through the medium, and isentropic bulk modulus. The values of these parameters directly influence the operation, performance and pollutant emissions of diesel engines. Primary results obtained demonstrate the possibilities of using what we call here the B25 blend with low-cost procedures and without major technical intervention in the equipment used to construct diesel engines. Two parameters important for the injection process (kinematic viscosity and density) show equal values for B25Us_irr ultrasonically irradiated for 350 seconds and diesel fuel ultrasonically irradiated for 420 seconds. The range of the achieved NOx pollutant emission reduction was between 18.2% for the ultrasonically irradiated blend B25Us_irr (no load) and 1.4% for the ultrasonically irradiated blend B100Us_irr (100% load), when compared with untreated basic biodiesel.

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“…So, the mixed fuel is particularly has the potential to achieve fast evaporation and relatively lean and homogeneous mixtures. The combination of the multiple fuel injection strategy with the Exhaust Gas Recirculation technique is studied as well [4]. The results from this study have demonstrated that the use of the multiple fuel injection strategy can effectively reduce the NOx emission from diesel engines.…”

Section: Introductionmentioning

confidence: 90%

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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A Numerical Study of Multiple Fuel Injection Strategies for NO_xReduction from DI Diesel Engines

Cited by 22 publications

References 18 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

Attempts to Reduce Biodiesel Blends Nox Pollutant Emissions by Ultrasonic Conditioning

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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A Numerical Study of Multiple Fuel Injection Strategies for NOxReduction from DI Diesel Engines

Cited by 22 publications

References 18 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

Attempts to Reduce Biodiesel Blends Nox Pollutant Emissions by Ultrasonic Conditioning

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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Product

Resources

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A Numerical Study of Multiple Fuel Injection Strategies for NO_xReduction from DI Diesel Engines