Late-Fuel Simulation Near Nozzle Outlet of Fuel Injector During Closing Valve

Ishii, Eiji; Yoshimura, Kazuyoshi; Yasukawa, Yoshihito; Ehara, Hideharu

doi:10.1115/1.4032885

Cited by 5 publications

(1 citation statement)

References 9 publications

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“…The simulation model (Figure 2) we used is the hybrid one we previously used (Ishii et al [15][16][17]). It integrates Yabe and Aoki's CIP method [18] with Koshizuka and Oka's MPS method [13].…”

Section: Simulation Modelmentioning

confidence: 99%

Simulation of Liquid Film Spreading on Tip of Spray Injector

Ishii¹,

Yoshimura²,

Hosaka³

2021

IJEPE

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The behaviors of fuel films adhering to the tip of a fuel injector for automotive gasoline direct-injection engines was simulated by the computational fluid dynamics. Liquid film adhering to the tip of the fuel injector is a source of carbon deposits; the film spreads on the surfaces of the tip and remains there under certain wetting conditions. The deposit build-up can clog the injector nozzles, which can alter the spray pattern, furthermore, deposits on the tips of injectors are a source of particulate matter (PM) discharged from the engine. In order to prevent air pollution, it is essential to develop a technology to reduce PM. The spread of fuel adhering to the tip of a fuel injector was simulated using the moving particle semi-implicit method, and a previously developed particle/grid hybrid method was used to study the effects of spray plumes. The simulated distribution of the film qualitatively agreed with the measured distribution of carbon deposits. Fuel film formed on the concave and convex wall surfaces. The fuel film and carbon deposits were unevenly distributed in the air flow direction. Investigation of the behaviors of floating droplets around the tip between fuel injections revealed that the droplets were pulled toward the tip wall due to a reverse air flow generated by the fuel plumes ejected by the injector nozzles. These droplets then merged as a part of the fuel film, which spread toward the injection nozzles due to the air flow directed at the nozzles. Some of the film was sucked into the spray plumes and then re-injected into the air region again. The simulated fuel film behaviors on the tip qualitatively agreed with the measured ones. Furthermore, the simulation showed that optimizing the surface shape of the fuel injector tip, particularly the concave portion, is important for reducing particulate matter.

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Section: Simulation Modelmentioning

confidence: 99%

Simulation of Liquid Film Spreading on Tip of Spray Injector

Ishii¹,

Yoshimura²,

Hosaka³

2021

IJEPE

Self Cite

View full text Add to dashboard Cite

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Applying surface tension as pressure boundary condition in free surface flow analysis by moving particle simulation method

2023

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A model that introduces surface tension as a pressure boundary condition, named the surface tension as pressure (STP) model, was developed for free surface flow analyses by the moving particle simulation (MPS) method. The STP model assigns to surface particles the liquid pressure of Laplace’s formula. The model is an alternative to previous models that apply surface tension as volume force such as the continuum surface force model. Problems that appeared when using the volume force models, such as the dependencies of calculation results on particle resolution and pressure gradient accuracy, were solved by using the STP model. Calculations predicted the theoretical values of the internal pressure of a 3D spherical droplet and the oscillation period of a 2D elliptic droplet over a wide range of surface tension coefficients and droplet sizes with errors less than 10%. Since the STP model is easy to implement, does not increase computation cost from previous models, and does not require surface reconstruction or additional marker particles, the model is suitable for practical and large-scale free surface flow problems that involve violent deformation of the liquid surface such as liquid atomization.

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Effects of Opening and Closing Fuel-Injector Valve on Air/Fuel Mixture

Ishii

Yoshimura

Yasukawa

et al. 2017

Journal of Engineering for Gas Turbines and Power

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Lower engine emissions like CO2, particulate matter (PM), and NOx have recently become more necessary in automobile engines to protect the earth's environment. Keeping uniformity of air/fuel mixture and decreasing fuel adhesion on walls of cylinder and piston are effective in order to reduce the engine emissions. In order to achieve the target fuel-spray, fuel injectors for gasoline direct injection engines need to be designed to deal with multiple injections with high speed of opening and closing of valves. One of the difficulties in the multiple injections is to control fuel-spray behaviors during opening and closing of valve; flow rate and spray penetration which are changed due to slow velocity of fluid during opening and closing of valve cause nonuniformity of air/fuel mixture that results in the increase of PM. Fuel-spray behaviors are controlled by the valve-lifts of fuel injectors; therefore, air/fuel mixture simulations that integrate with inner flow simulations in fuel injectors during the opening and closing of valves are essential for studying the effects of valve motions on air/fuel mixtures. In this study, we developed an air/fuel mixture simulation that is connected with an inner-flow simulation with a valve opening and closing function. The simulation results were validated by comparing the simulated fuel breakup near the nozzle outlets and the air/fuel mixtures in the air region with the measured ones, revealing good agreement between them. The effects of opening and closing the valve on the air/fuel mixtures were also studied; the opening and closing of the valve affected the front and rear behaviors of the air/fuel mixture and also affected spray penetrations. The developed simulation was found to be an effective tool for studying the effects of valve motions on the air/fuel mixtures. It was also found that the magnetic circuit with the solenoid needs to be designed to achieve high-speed valve motion and also keeps same valve motion in each injection, especially during opening and closing of valve.

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Late-Fuel Simulation Near Nozzle Outlet of Fuel Injector During Closing Valve

Cited by 5 publications

References 9 publications

Simulation of Liquid Film Spreading on Tip of Spray Injector

Simulation of Liquid Film Spreading on Tip of Spray Injector

Applying surface tension as pressure boundary condition in free surface flow analysis by moving particle simulation method

Effects of Opening and Closing Fuel-Injector Valve on Air/Fuel Mixture

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