Effect of back pressure on nozzle inner flow in fuel injector

Qiu, Tao; Xiao, Song; Lei, Yan; Dai, Houde; Cao, Chen; Xu, Hongtao; Feng, Xiang

doi:10.1016/j.fuel.2016.01.044

Cited by 55 publications

(22 citation statements)

References 18 publications

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“…= 12% [18,19,[53][54][55]. Still, this nozzle is expected to cavitate well before the mass flow rate choke conditions [39,54,55]. All the experimental results presented in this manuscript are available for download at: http://www.cmt.upv.es/DD01.aspx.…”

Section: Axial Distance [Mm]mentioning

confidence: 99%

The effect of nozzle geometry over internal flow and spray formation for three different fuels

Payri

Viera

Gopalakrishnan

et al. 2016

Fuel

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h i g h l i g h t sTwo single hole nozzle (cylindrical and convergent) are used. A complete hydraulic characterization is done along with spray visualization. A fast pulsed light source is synchronized to a fast camera working at 160 kHz. The effect of nozzle geometry is analyzed for three different fuels. A large set of experimental data was obtained, which could be used for model validation. a b s t r a c tThe influence of internal nozzle flow characteristics over macroscopic spray development is studied experimentally for two different nozzle geometries and three fuels. The measurements include a complete hydraulic characterization consisting of instantaneous injection rate and spray momentum flux measurements, followed by a high-speed visualization of isothermal liquid spray in combination with cylindrical and conical nozzle configurations. Two of the fuels are pure components-n-heptane and ndodecane-while the third fuel consists of a three-component surrogate to better represent the physical and chemical properties of diesel fuel. The cylindrical nozzle with 8.6% larger diameter, in spite of higher mass flow rate and momentum flux, shows slower spray tip penetration when compared to the conical nozzle. The spreading angle is found to be inversely proportional to the spray tip penetration. The spreading angle is largely influenced by the nozzle geometry and the ambient density. Rail pressure was found to have weak influence on the near-field spreading angle and no influence on the standard deviation of the spreading angle. n-Heptane spray shows slowest penetration rates while n-dodecane and the surrogate fuel mixture show very similar spray behavior for variations in injection pressure and back pressure. However, the surrogate fuel mixture shows higher penetration than n-dodecane when using the conical nozzle and lower penetration than n-dodecane when using cylindrical nozzle.

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Section: Axial Distance [Mm]mentioning

confidence: 99%

The effect of nozzle geometry over internal flow and spray formation for three different fuels

Payri

Viera

Gopalakrishnan

et al. 2016

Fuel

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“…A i is defined as the region of vapor volume fraction that is over 1% in the radial direction (Li, Liu, Wei, Liang, & Tang, 2018;Qiu et al, 2016a). Figure 8(b) shows the relationship between A m and P in on plane C, which is the central position of five planes.…”

Section: Cavitation Development Process In Radial Directionmentioning

confidence: 99%

Influence of inlet pressure on cavitation characteristics in regulating valve

Liu

et al. 2020

Engineering Applications of Computational Fluid Mechanics

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The cavitation development process in regulating valve under different inlet pressures is investigated experimentally and numerically in our paper. The influence of inlet pressure P in on cavitation location, shape, area and intensity is studied in axial and radial directions, and the axial and radial pressure distributions are also analyzed. The cavitation is generally annular in shape radially and irregular polygon in shape axially. Cavitation bubbles occur at the throat entrance when the inlet pressure increases. The bubbles then accumulate, and a bubble ring is formed. The cavitation development process under different inlet pressures is separated into three stages, no-cavitation, initial cavitation and steady-cavitation stages. During the no-cavitation stage, no bubbles exist. During the initial cavitation stage, bubbles occur and the area and intensity of cavitation increase in the radial and axial directions with increasing inlet pressure. During the steady-cavitation stage, the calculation area and intensity of bubble rings reach their maximum values and then remain stable. The cavitation bubbles extend downstream, and the area of cavitation ring and cavitation intensity increase with increasing inlet pressure. A slit exists between the upper and lower parts of bubbles in the cavitation process, both parts touch each other forming a whole.

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“…Further, some other parameters that have been proved to have a big influence on the internal fluid flow and the injection process, i.e. cavitation and the back pressure, were taken into consideration [8]. Using a verified 3D injector model, the researchers developed numerical simulations which showed that, for a given injection pressure, cavitation occurs with a decrease in back pressure.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Fuel Flow Patterns at the Nozzle Exit Considering Different Fuels and Operating Parameters of a Diesel Engine

Motogna

Moldovanu

Mariașiu

2019

TFAMENA

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The paper presents a numerical study (Eulerian multiphase approach) on the influence of physical characteristics of different fuels (density and dynamic viscosity) on the fuel flow pattern at the injection nozzle exit considering different fuels and operating parameters of a diesel engine (fuel temperature and compression ratio). A new term, Nozzle Uniformity Coefficient (NUC) was introduced to define the fluid flow pattern at the injection nozzle exit and to correlate its value with a further development of the spray in the combustion chamber. The results of the analysis show that the structure of the fluid flow pattern is the most homogeneous in the case of low fuel temperatures and low back pressures. Fuel velocities have an immediate effect on the spray development, the air-fuel mixing process, and the depth of jet penetration into the combustion chamber. The average values of biodiesel fuel velocities are lower compared to those of diesel fuel. In view of the increasing use of fuels from renewable sources (biofuels), a logical conclusion is that it is necessary to correlate the injection system components with their physicochemical properties.

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Effect of back pressure on nozzle inner flow in fuel injector

Cited by 55 publications

References 18 publications

The effect of nozzle geometry over internal flow and spray formation for three different fuels

The effect of nozzle geometry over internal flow and spray formation for three different fuels

Influence of inlet pressure on cavitation characteristics in regulating valve

Numerical Analysis of Fuel Flow Patterns at the Nozzle Exit Considering Different Fuels and Operating Parameters of a Diesel Engine

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