The Influence of Needle Eccentric Motion On Hole-to-Hole Injection Characteristics of a Two-Layered 8-Hole Diesel Injector

2021 ◽  
Author(s):  
Tianyu Jin ◽  
Yu Sun ◽  
Chuqiao Wang ◽  
Adams Moro ◽  
Xiwen Wu ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Injection Rate ◽  
Hole Injection ◽  
Three Dimensional Model ◽  
Maximum Displacement ◽  
Fuel Flow ◽  
Diesel Injection ◽  
Eccentric Motion

Abstract The stringent emission regulations diesel engines are required to meet has resulted in the usage of multi-hole and ultra-multi-hole injectors, nowadays. In this research study, a double layered 8-hole diesel injection nozzle was investigated both numerically and experimentally. A three-dimensional model of the nozzle which was validated with experimental results was used to analyze the injection characteristics of each hole. The validation was conducted by comparing experiment and simulation injection rate results, acquired simultaneously from all the holes of the injector and the model. The fuel flow rates of the lower layered holes are higher than those of the upper layered holes. Two different needle eccentricity models were established. The first model only included the lateral displacement of the needle during needle lift. The needle reached maximum displacement at full needle lift. The second model considered the needle inelastic deformation into consideration. The needle radially displaces and glides along with the needle seat surface during needle lift. When the eccentricity reached maximum in the radial direction, the needle began to lift upwards vertically. The differences in injection characteristics under the different eccentricity models were apparent. The results indicated that the cycle injection quantity, fuel injection rate and cavitation of each hole were affected during the initial lifting stages of the needle lift. As the eccentricity of the needle increases, the injection rate uniformity from the nozzle hole deteriorates. The result showed that the upper layered holes were affected by the needle eccentricity during needle lift.

scholarly journals Safety Evaluation of Underground Caverns Based on Monte Carlo Method

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Qifeng Guo ◽  
Zhihong Dong ◽  
Meifeng Cai ◽  
Fenhua Ren ◽  
Jiliang Pan
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Cumulative Distribution ◽  
Three Dimensional Model ◽  
Maximum Displacement ◽  
The Monte Carlo Method ◽  
Underground Caverns ◽  
The Stability

In order to study the influence of joint fissures and rock parameters with random characteristics on the safety of underground caverns, several parameters affecting the stability of surrounding rock of underground caverns are selected. According to the Monte Carlo method, random numbers satisfying normal distribution characteristics are established. A three-dimensional model of underground caverns with random characteristics is established by discontinuous analysis software 3DEC and excavation simulations are carried out. The maximum displacement at the numerical monitoring points of arch and floor is the safety evaluation index of the cavern. The probability distribution and cumulative distribution function of the displacement at the top arch and floor are obtained, and the safety of a project is evaluated.

Active Control Analysis for Combustion-Driven Dynamic Instabilities in Gas-Turbine Combustors

2000 ◽  
Author(s):  
M. A. Mawid ◽  
T. W. Park ◽  
B. Sekar
Keyword(s):  
Heat Release ◽  
Gas Turbine ◽  
Active Control ◽  
Fuel Injection ◽  
Time Lag ◽  
Injection Rate ◽  
Control Analysis ◽  
Time Lags ◽  
Viscous Effects ◽  
Fuel Flow

A one-dimensional combustor model has been used to simulate combustion-driven dynamic instabilities and then-active control in a generic gas turbine combustor. The combustor model accounts for the unsteady heat release and viscous effects along with choked and open boundaries. Combustion is modeled by using global kinetics for JP-8 fuel. The active control methodology simulated in this study was based upon modulating the primary fuel injection rate. A sinusoidal functional form was implemented to pulse the fuel flow at various frequencies and amounts of pulsated fuel. The numerical results showed that the combustor unstable modes were captured and pressure limit cycle oscillations were attained for certain time lags between the instant of fuel-air mixture injection and heat release. The results also exhibited the effect of varying the time lag to damp out the instability. The simulations also showed that fuel pulsation with frequencies greater or less than the combustor resonant frequencies can suppress the unstable modes.

Spray Formation and Fuel Flow Rate at the Multi-Stage Injections Injected From the Swirl Nozzle

2003 ◽  
Author(s):  
Kokichi Sawada ◽  
Shinji Nakao ◽  
Tsuneaki Ishima ◽  
Tomio Obokata ◽  
Katsuyoshi Kawachi ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Pressure Oscillation ◽  
Injection Rate ◽  
Fuel Flow Rate ◽  
Two Stage ◽  
Fuel Flow ◽  
Piv Measurement ◽  
Valve Opening

The structure, droplet characteristics and instantaneous fuel injection rate of two stage injection spray designed for direct injection gasoline engine were analyzed experimentally. A particle image velocimetry (PIV) to evaluate the instantaneous two-dimensional velocity field, a phase Doppler anemometer (PDA) and an instantaneous fuel flow rate meter based on a laser Doppler anemometer (LDA flow rate meter) were applied for the measurements. A swirl nozzle injector was used and injection conditions were 25 Hz of spray frequency, 2 ms and 1ms of the first and the second injection durations and 2.4, 3.3 and 9.1 ms of valve opening intervals. The initial jet of the second stage injection can overtook the main spray body of the first stage injection under the valve opening interval of 2.4 and 3.3 ms. The LDA flow rate meter made the injection rate measurement with sufficient accuracy in the two stage injection and showed the unstable second injection due to remaining pressure oscillation in the injection pipe. Both time averaged and time resolved PDA results were compared in the intermittent spray. The interaction between the first and the second sprays was also demonstrated in vector map obtained by the PIV measurement.

Inline Pump Internal Flow Characterization for Optimized Diesel Injection

2008 ◽  
Author(s):  
G. Chiatti ◽  
O. Chiavola ◽  
F. Palmieri
Keyword(s):  
Formation Control ◽  
Fuel Injection ◽  
Three Dimensional ◽  
Internal Flow ◽  
Injection Rate ◽  
Local Pressure ◽  
Injection Process ◽  
Flow Characterization ◽  
Dimensional Simulation ◽  
And Performance

The injection process optimization plays a key role in diesel engine development activities, both for pollutant formation control and performance improvement. The present paper focuses on relatively small diesel units, equipped with fully mechanical injection systems; in detail, the considered system layout is based on the use of spring injectors; the amount of delivered fuel is controlled by the positioning of the pump plunger groove. The paper highlights the role of the inline pump and the influence of fuel characteristics on the system operation. By means of a three-dimensional numerical flow study, the behavior of pump fuel passages and delivery valve is simulated. Then, on the basis of the system features, a complete lumped/one-dimensional numerical model is realized, in which the discharge coefficients evaluated through the three-dimensional simulation are employed. Fuel injection rate and local pressure time histories are investigated, paying specific attention to the occurrence of the relevant phenomena in the system components. Obtained results are compared with experimental data.

An Instrument for Measuring Orifice-Specific Fuel-Injection Rate From a Multi-Orifice Nozzle

2008 ◽  
Author(s):  
Jason G. Kempenaar ◽  
Charles J. Mueller ◽  
Kim A. Shollenberger ◽  
Krishna Lakshminarasimhan
Keyword(s):  
Fuel Injection ◽  
Injection Rate ◽  
Geometric Constraints ◽  
Thermal Shield ◽  
Injector Nozzle ◽  
Compression Ignition Engines ◽  
Fuel Flow ◽  
Transducer Output ◽  
Effects Of Temperature ◽  
Fuel Injection Rate

Understanding fuel-injection processes is important for improving combustion in compression-ignition engines. To understand and model injection processes in detail, it is necessary to measure the instantaneous mass flow rate of fuel through each orifice of the injector nozzle. Due to constraints from injector design and operation, injection rate is typically measured downstream from the orifice exit. Measuring injection rate from a multi-orifice nozzle adds several geometric constraints, particularly when measuring fuel flow from a single orifice. The injection ratemeter discussed in this paper is designed to fit inside an optical research engine so that the injection rate can be measured without having to place the injector in an external fixture. The injection rate is calculated from a measurement of the momentum flux of a jet of fuel impinging upon the surface of a piezoelectric force (or pressure) transducer, combined with a measurement of the quantity of fuel injected, as demonstrated previously [1–3]. The ratemeter includes a thermal shield to limit the effects of temperature fluctuations on the transducer output. Data were acquired for one injector nozzle at several different injection durations and compared to results from literature for similar injector designs. Estimates for the uncertainty of the measured injection rates are provided and the calibration technique used is presented.

3-D Numerical Simulation on Micro-Hole of the Common-Rail Pipe Abrasive Flow Machining

2013 ◽  
Vol 437 ◽  
pp. 202-206
Author(s):  
Hao Guo ◽  
Jun Ye Li ◽  
Teng Fei Ma
Keyword(s):  
Numerical Simulation ◽  
Fuel Injection ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Common Rail ◽  
Injection System ◽  
Three Dimensional Model ◽  
Abrasive Flow Machining ◽  
Micro Hole ◽  
The Common

Common-rail pipe is an important component of fuel injection system, whose inner cavity is hidden and requires a high precision. So that the general mechanical processing is difficult to achieve, while abrasive flow machining just be able to solve this problem. In this article, the three-dimensional model of common-rail pipe is established and meshed by GAMBIT, next the mesh file is read into FLUENT, and then the Mixture model is used for numerical simulation. By analyzing the simulation results, we can get how will the pressure difference between inlet and outlet, the volume fraction of abrasive, and the processing order impact on the processing quality. Finally, a reasonable processing program is proposed for the common-rail pipe.

scholarly journals Deformation Response Research of the Existing Subway Tunnel Impacted by Adjacent Foundation Pit Excavation

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xin Dong ◽  
Ling Mei ◽  
Shuyan Yang ◽  
Liang He
Keyword(s):  
Axial Strain ◽  
Retaining Wall ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Subway Tunnel ◽  
Three Dimensional Model ◽  
Foundation Pit ◽  
Maximum Displacement ◽  
Initial Stress State ◽  
Surrounding Soil

The excavation of foundation pits is one of the most important factors causing changes to the initial stress state of its surrounding soil, thus affecting the safety of nearby existing subway tunnels. In order to study the deformation in metro lines induced by adjacent foundation pit excavation, a three-dimensional model based on an actual engineering case was established, and the deformation regulations of the retaining wall, surrounding soil, and tunnels were investigated, which also validated the model’s feasibility. Additionally, the deformation and strain response of the subway tunnel under different selection parameters of the enclosing structure and soil were studied. The results showed that, after the foundation pit excavation, the soil inside the pit underwent an uplift, the surrounding soil outside of the pit showed vertical settlement, and the retaining wall created a deformation towards the interior of the pit. Mechanical parameters of plate elements have a small influence on the deformation of metro lines. Axial strain and maximum displacement of the subway tunnel increase with the increase in the soil’s Poisson’s ratio, and on the contrary, they decrease with the increase in the m-value and G 0 , ref . The maximum responses of the subway tunnel came from changes to G 0 , ref and υ . These analysis results can be used for the safety evaluation of subway tunnel operation, design, and construction in other similar engineering settings.

scholarly journals Combined effects of combustion chamber geometry and injection strategy on combustion and emissions of a diesel engine

2021 ◽  
Vol 268 ◽  
pp. 01026
Author(s):  
Jizhou Zhang ◽  
Fuwu Yan ◽  
Yu Wang
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Fuel Injection ◽  
Direct Injection ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Complete Combustion ◽  
Injection Strategy ◽  
Injection Duration ◽  
Chamber Volume

For a certain type of direct injection diesel engine, a three-dimensional model of a single-cylinder complete combustion chamber and in-take/exhaust port was established. Three-dimensional Computational Fluid Dynamics (CFD) analysis software CONVERGE was used for simulation. The effects of fuel injection strategy and combustion chamber geometry on combustion emissions of diesel engine were studied while the combustion chamber volume, engine compression ratio, total fuel injection quantity and total injection duration were kept unchanged. The results show that the strategy of multiple injection and reasonable shape of combustion chamber can effectively increase the turbulent kinetic energy in cylinder, improve the uniformity of oil-gas mixing, reduce the emission of pollutants, and increase the quality of after injection can further reduce the emissions of NOx and soot.

scholarly journals Uncertainty Analysis of Factors Influencing Stimulated Fracture Volume in Layered Formation

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4444 ◽  
Author(s):  
Jingxuan Zhang ◽  
Xiangjun Liu ◽  
Xiaochen Wei ◽  
Lixi Liang ◽  
Jian Xiong ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Prediction Equation ◽  
Injection Rate ◽  
Rock Properties ◽  
Three Dimensional Model ◽  
Stimulated Reservoir Volume ◽  
Reservoir Volume ◽  
Layered Formation

Hydraulic fracture dimension is one of the key parameters affecting stimulated porous media. In actual fracturing, plentiful uncertain parameters increase the difficulty of fracture dimension prediction, resulting in the difficulty in the monitoring of reservoir productivity. In this paper, we established a three-dimensional model to analyze the key factors on the stimulated reservoir volume (SRV), with the response surface method (RSM). Considering the rock properties and fracturing parameters, we established a multivariate quadratic prediction equation. Simulation results show that the interactions of injection rate (Q), Young’s modulus (E) and permeability coefficient (K), and Poisson’s ratio (μ) play a relatively significant role on SRV. The reservoir with a high Young’s modulus typically generates high pressure, leading to longer fractures and larger SRV. SRV reaches the maximum value when E1 and E2 are high. SRV is negatively correlated with K1. Moreover, maintaining a high injection rate in this layered formation with high E1 and E2, relatively low K1, and μ1 at about 0.25 would be beneficial to form a larger SRV. These results offer new perceptions on the optimization of SRV, helping to improve the productivity in hydraulic fracturing.

Hydraulic modelling of brown trout habitat in a hydropower-impacted Alpine braided stream

2020 ◽  
Author(s):  
Yufang Ni ◽  
Stuart N. Lane
Keyword(s):  
Environmental Flows ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Suitable Habitat ◽  
Detached Eddy Simulation ◽  
Three Dimensional Model ◽  
Ice Melt ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation ◽  
Alpine Streams

<p>Braided rivers have complex and dynamic bed morphologies. In Alpine streams, they may be impacted upon by natural flow variability (e.g. snow and ice melt) that can lead to the lateral displacement of suitable habitat. To date, this process has been investigated in two-dimensional models due to the difficulty of applying fully three-dimensional computational fluid dynamics at the scale of river reaches. This is problematic because lateral and vertical variations in kinetic energy and vorticity and their change through time are crucial determinants of where good habitat is found and where it migrates to as river discharge changes. Here we attempt a reach-scale three-dimensional model of stream habitat using the open-source toolbox OpenFoam, with turbulence resolved by Delayed Detached Eddy Simulation (DDES), to model the flow structures in a braided reach of the Turtmanna, a tributary of the Rhône river, Switzerland. The results show that locations deemed suitable in a 2D solution are not when looked at in 3D, and vice versa. This result has important implications for the use of hydraulic habitat modelling for the design of environmental flows in human impacted Alpine streams.</p>

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