Scaling Laws for Free Turbulent Gas Jets and Diesel-Like Sprays

“…An additional important feature concerning the radial evolution of axial velocity and fuel concentration is self-similarity. Rajaratnam (1976), among others (Abramovich 1963;Hinze 1975;Sinnamon et al 1980;Lefèbvre 1989;Desantes et al 2006b), found that, for any section in the fully developed region of the spray, if the velocity at any radial position is divided by the centreline velocity and plotted versus the normalized radius (r/R), where r is the radial coordinate and R the spray radius defined from the velocity angle θ u (see figure 1), it has a single evolution.…”

Section: Introductionmentioning

confidence: 99%

“…Previous analyses have shown that axial concentration and velocity can be related with the aid of the Schmidt number (Desantes et al 2006b). In particular, the following expression has shown to perform properly in the near-nozzle field:…”

mentioning

confidence: 99%

Study of mass and momentum transfer in diesel sprays based on X-ray mass distribution measurements and on a theoretical derivation

et al. 2010

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In this paper a research aimed at quantifying mass and momentum transfer in the near-nozzle field of diesel sprays injected into stagnant ambient air is reported. The study combines x-ray measurements for two different nozzles and axial positions, which provide mass distributions in the spray, with a theoretical model based on momentum flux conservation which was previously validated. This investigation has allowed the validation of Gaussian profiles for local fuel concentration and velocity near the nozzle exit, as well as the determination of Schmidt number at realistic diesel spray conditions. This information could be very useful for those who are interested in spray modelling, especially at high pressure injection conditions.

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“…It is interesting to remark that, at 7.7 bar gross IMEP, soot emissions were under the detection limit of the smoke meter for all the fuels. This is due to the high PER used (low diesel amount injected) and the large advance of the diesel injection timing [43], which provides enough mixing time to avoid soot formation [44]. Focusing on CO and HC emissions, it is possible to state that, as a general trend, the operation with biofuels results in higher levels of unburned products than with regular diesel and gasoline fuels.…”

Section: Fuel Autoignition Qualities Modificationmentioning

confidence: 99%

Dual-Fuel Combustion for Future Clean and Efficient Compression Ignition Engines

et al. 2016

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Stringent emissions limits introduced for internal combustion engines impose a major challenge for the research community. The technological solution adopted by the manufactures of diesel engines to meet the NOx and particle matter values imposed in the EURO VI regulation relies on using selective catalytic reduction and particulate filter systems, which increases the complexity and cost of the engine. Alternatively, several new combustion modes aimed at avoiding the formation of these two pollutants by promoting low temperature combustion reactions, are the focus of study nowadays. Among these new concepts, the dual-fuel combustion mode known as reactivity controlled compression ignition (RCCI) seems more promising because it allows better control of the combustion process by means of modulating the fuel reactivity depending on the engine operating conditions. The present experimental work explores the potential of different strategies for reducing the energy losses with RCCI in a single-cylinder research engine, with the final goal of providing the guidelines to define an efficient dual-fuel combustion system. The results demonstrate that the engine settings combination, piston geometry modification, and fuel properties variation are good methods to increase the RCCI efficiency while maintaining ultra-low NOx and soot emissions for a wide range of operating conditions.

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Scaling Laws for Free Turbulent Gas Jets and Diesel-Like Sprays

Cited by 36 publications

References 8 publications

Estimation of a suitable Schmidt number range in diesel sprays at high injection pressure

Estimation of a suitable Schmidt number range in diesel sprays at high injection pressure

Study of mass and momentum transfer in diesel sprays based on X-ray mass distribution measurements and on a theoretical derivation

Dual-Fuel Combustion for Future Clean and Efficient Compression Ignition Engines

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