Numerical research of diesel spray and atomization coupled cavitation by Large Eddy Simulation (LES) under high injection pressure

Yin, Bifeng; Yu, Shengwei; Jia, Huang; Yu, Jun

doi:10.1016/j.ijheatfluidflow.2016.01.005

Cited by 56 publications

(23 citation statements)

References 31 publications

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“…First, the dynamic behavior of the injection system has a significant impact on aspects such as the injection and combustion duration [5][6][7] or the combustion noise [8,9]. Additionally, the flow conditions at the injector nozzle outlet affect the spray atomization and fuel-air mixing efficiency [10][11][12][13][14]. Improving atomization and mixing can be particularly important in modern engines, since it can help to increase the usage of Exhaust Gas Recirculation (EGR) [15,16], necessary to comply with more stringent certification requirements regarding nitrogen oxides (NOx) [17].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance

Salvador

López

Morena

et al. 2018

Fuel

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Nozzle hydraulic performance has a significant impact on diesel spray development and combustion characteristics. Thus, it is important to understand the links between the nozzle geometry, the internal flow features and the spray formation. In this paper, a detailed analysis of the impact of the nozzle orifices inclination angle on its hydraulic performance is performed. For this purpose, three different nozzles with included angles of 90, 140 and 155 degrees are evaluated. Instantaneous injection rate and momentum flux are measured on a set of injector operating conditions (mainly injection pressure and discharge pressure). The results show that higher inclination angles lead to smaller mass 2 flow and momentum flux at steady-state conditions, due to the higher losses at the orifice inlet. These losses are translated in lower both area and velocity coefficients. Nevertheless, the impact of this parameter is limited thanks to the counteracting effect of the hydrogrinding process, which produces larger rounding radii at the orifice inlet as the included angle increases. Based on the experimental results, correlations of the discharge coefficient as a function of the Reynolds number are obtained and evaluated.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance

Salvador

López

Morena

et al. 2018

Fuel

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“…When the backpressure is set as 1 MPa, cavitation bubbles occur at the throat entrance and develop downstream with increasing P in . When the oil flows to the contraction section of the flow passage, the flow direction changes because of the decrease in geometric area, which induces increasing velocity and decreasing liquid pressure (Yin et al, 2016). If the liquid pressure is below the saturated vapor pressure (P v ), then cavitation incepts can be found (Qiu et al, 2016b).…”

Section: Resultsmentioning

confidence: 99%

“…The fluid inside the regulating valve is a complex multiphase flow Zheng, Ou, Yi, et al, 2016), and a transformation from liquid to vapor exists when bubbles occur. Based on the Navier-Stokes equation, the gas-liquid phase is considered continuous, and the mixture model is often selected to describe multiphase flow (Qiu et al, 2018b;Yin, Yu, Jia, & Yu, 2016).…”

Section: Numerical Simulationmentioning

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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“…The main reason is the compressibility and the large density gradient in the region that is close to cavitation clouds, and an accurate prediction on eddy viscosity is important for the simulation. Large Eddy Simulation (LES) has the ability to provide good results for cavitating simulation [20,21]. However, it is time-consuming and has a seriously high requirement for mesh quality.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of a High-Pressure Submerged Jet Using a Cavitation Model Considering Effects of Shear Stress

Yang

Shi

et al. 2019

Processes

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In the current research, a high-pressure submerged cavitation jet is investigated numerically. A cavitation model is created considering the effect of shear stress on cavitation formation. As such, this model is developed to predict the cavitation jet, and then the numerical results are validated by high-speed photography experiment. The turbulence viscosity of the renormalization group (RNG) k-ε turbulence model is used to provide a flow field for the cavitation model. Furthermore, this model is modified using a filter-based density correction model (FBDCM). The characteristics of the convergent-divergent cavitation nozzle are investigated in detail using the current CFD simulation method. It is found that shear stress plays an important role in the cavitation formation in the high-pressure submerged jet. In the result predicted by the Zwart-Gerber-Belamri (ZGB) cavitation model, where critical static pressure is used for the threshold of cavitation inception, the cavitation bubble only appears at the nozzle outlet and the length of the cavity is much shorter than the actual length captured by the high-speed photography experiment. When the shear stress term is added to the critical pressure, the length of the predicted cavity is close to the experimental result and three phenomena of the jet are captured, namely, growth, shedding, and collapsing, which agrees well with the experimental high-speed image. According to the orthogonal analysis based on the simulation result, when the jet power is unchanged, the main geometry parameter of the divergent-convergent nozzle that affects the jet performance is the divergent angle. For the nozzle with three different divergent angles of 40°, 60°, and 80°, the one with the medium angle generates the most intensive cavitation cloud, while the small one shows the weakest cavitation performance. The obtained simulation result is confirmed by cavitation erosion tests of the Al1060 plate using these three nozzles.

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Numerical research of diesel spray and atomization coupled cavitation by Large Eddy Simulation (LES) under high injection pressure

Cited by 56 publications

References 31 publications

Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance

Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 1 – Hydraulic performance

Influence of inlet pressure on cavitation characteristics in regulating valve

Numerical Investigation of a High-Pressure Submerged Jet Using a Cavitation Model Considering Effects of Shear Stress

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