Diesel spray and combustion of multi-hole injectors with micro-hole under ultra-high injection pressure – Non-evaporating spray characteristics

Zhai, Chang; Jin, Yu; Nishida, Keiya; Ogata, Youichi

doi:10.1016/j.fuel.2020.119322

Cited by 46 publications

(13 citation statements)

References 40 publications

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“…35 Moreover, the diffusion rate is higher than the evaporation rate before entering the steady state, and higher injection pressure would cause a larger diffusion rate, which increases the liquid-phase penetration. 36 After entering the steady state, a dynamic equilibrium appears between diffusion and evaporation rates. 37 And the variation law of liquid-phase penetration depends on the increase rate in the diffusion and evaporation rates.…”

Section: Resultsmentioning

confidence: 99%

Experimental study on spray diffusion characteristics at various biodiesel-butanol blended ratios and ambient conditions

Zhang

Xia

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The depletion of fossil fuels and stringent emission regulations have encouraged the development of renewable fuels, especially biodiesel and alcohols fuels. The aim of the investigation is to explore the spray diffusion characteristics at different biodiesel-butanol blended ratios (0, 10%, 30%, 50%), ambient temperatures (600 K, 700K, 800 K) and pressures (1 MPa, 3MPa, 5 MPa). The experiment was carried out in a constant-volume combustion chamber. The liquid- and vapor-phase spray images were captured by backlight illumination and schlieren imaging technique, respectively. The axial, radial and spatial diffusion characteristics were analyzed, including spray penetration, cone angle, area, R-parameter and perimeter ratio. Results show that in the case of biodiesel mixed with 10% n-butanol, for liquid-phase spray, the liquid-core spray with high concentration has the largest impact on axial diffusion, and for vapor-phase spray, axial dispersion is slower and radial diffusion is faster. The fuel density and ambient temperature have a more significant impact on the liquid-phase axial dispersion at the steady-state compared with ambient pressure and injection pressure. At lower ambient pressures, increasing the injection pressure can accelerate the radial diffusion and increase the spray cone angle, which is opposite of the variation law at higher ambient pressures. The radial spray has a faster diffusion with adding a small or middle proportion of n-butanol, and the maximum values of liquid- and vapor-phase cone angles appear at biodiesel blended with 30% and 10% n-butanol, respectively. Moreover, the axial diffusion plays a dominant role in the spray spatial dispersion.

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Section: Resultsmentioning

confidence: 99%

Experimental study on spray diffusion characteristics at various biodiesel-butanol blended ratios and ambient conditions

Zhang

Xia

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Vapor penetrations of target sprays are shown in Figure 10. Expectedly, larger nozzle hole size injector promotes longer vapor penetration, like spray penetration in non-evaporating condition 46,47 ; hence, it can be approximated that the vapor penetration depends on the injection momentum. Furthermore, simulated sprays draw an interesting observation.…”

Section: Macroscopic Characteristicsmentioning

confidence: 99%

Evaluation of multi-hole diesel injectors spray under evaporating conditions: Effects of adjacent spray plumes on the macroscopic and mixture characteristics of target spray

Safiullah

Ray

Nishida

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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Previously, diesel sprays of multi-hole injectors were simulated in an environment where only a single spray plume was simulated. Although boundaries were declared as symmetry, the impact of aerodynamic forces between spray plumes was always neglected. In the present work, all spray plumes of diesel injectors are simulated in a cylindrical box mesh considering external effects including umbrella angle, space between nozzle holes, and hole length to hole diameter ratio. To examine the nozzle hole size effect, two 10-hole diesel injectors with hole diameters of 0.101 and 0.133 mm are investigated under 120 MPa injection pressure. Likewise, to understand the effect of injection pressure, the 0.101 mm hole diameter injector is studied under 120 and 140 MPa rail pressures. In experiments, Laser Absorption Scattering diagnostic technique is applied to visualize the vapor phase, measure mixture concentration and characterize air entrainment. Since Diesel fuel does not absorb UV light, Tracer fuel with the composition of 97.5% of n-tridecane and 2.5% α-Methylnaphthalene is used. On the contrary, sprays are simulated in the Eulerian-Lagrangian two-phase fluid framework using KHRT Breakup and Multicomponent Evaporation models. Parameters such as injection rate and initial spray trajectory angle are measured experimentally and used as input for the spray simulation. Computational results correspond with experiments particularly in terms of Penetration and Equivalence Ratio while Spray Angle deviates.

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“…where L is the spray length. The entrainment rate is calculated using the spray volume values of the two consecutive instances [36]:…”

Section: Air Entrainment Into the Spray Plumementioning

confidence: 99%

New insight into air/spray boundary interaction for diesel and biodiesel fuels under different fuel temperatures

Ghandilou

Taghavifar

2022

Biofuels

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The liquid fuel breakup mechanism in spray injection with ambient air for diesel and biodiesel at different fuel temperatures is studied numerically. We find that biodiesel fuel type injection with low fuel temperature induces more air entrainment volume to the boundary of the spray than diesel fuel injection and higher fuel temperature. Meanwhile, the normalized parcel density for biodiesel is 12% larger than that of diesel and peaks at a shorter distance along the spray line from the injection point (42 vs. 46 mm). Biodiesel fuel demonstrates a maximum 0.395 mg/s of air mass flow while diesel max mass flow is 0.279 mg/s. As a result, the air entrainment volume of biodiesel to the moving spray area at 1.4 ms reaches 3723.98 mm 3 while for diesel the amount is 3151.27 mm 3 . However, the absorbed y-direction air velocity into the spray core for diesel fuel is dominant. The results give new insights into air exchange to spray boundary in the near nozzle and spray tip area: towards the tip of spray the air pushout is remarkable. Higher fuel temperature leads to slightly lower air exchange flow and entrainment (5.2%), cone angle reduction from 300 to 325 K fuel temperature, and increased surface area:volume ratio for diesel.

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Diesel spray and combustion of multi-hole injectors with micro-hole under ultra-high injection pressure – Non-evaporating spray characteristics

Cited by 46 publications

References 40 publications

Experimental study on spray diffusion characteristics at various biodiesel-butanol blended ratios and ambient conditions

Experimental study on spray diffusion characteristics at various biodiesel-butanol blended ratios and ambient conditions

Evaluation of multi-hole diesel injectors spray under evaporating conditions: Effects of adjacent spray plumes on the macroscopic and mixture characteristics of target spray

New insight into air/spray boundary interaction for diesel and biodiesel fuels under different fuel temperatures

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