scholarly journals Research on the internal flow and macroscopic characteristics of a diesel fuel injection process

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255874
Author(s):  
Hua Xia
Keyword(s):  
Fuel Injection ◽  
Cone Angle ◽  
Injection Pressure ◽  
Internal Flow ◽  
Spray Angle ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Injection Process ◽  
Wide Range ◽  
Diesel Fuel Injection

The internal flow and macroscopic spray behaviors of a fuel injection process were studied with schlieren spray techniques and simulations. The injection pressures(Pin)and ambient pressures(Pout)were applied in a wide range. The results showed that increasing the Pin is likely to decrease the flow performance of the nozzle. Furthermore, increasing the Pin can increase the spray tip penetration. However, the effect of Pin on the spray cone angle was not evident. The spray cone angle at an injection pressure of 160MPa was 21.7% greater than at a pressure of 100MPa during the initial spraying stage. Additionally, the discharge coefficient increased under high Pout, and the decrease in Pout can promote the formation of cavitation. Finally, increasing the Pout can decrease the penetration, while the spray angle becomes wider, especially at the initial spray stage, and high Pout will enhance the interaction of the spray and the air, which can enhance the spray quality.

Effect of Injection Rate Shaping Over Diesel Spray Development in Non Reacting Evaporative Conditions

2012 ◽  
Author(s):  
Raul Payri ◽  
Jaime Gimeno ◽  
Michele Bardi ◽  
Alejandro Plazas
Keyword(s):  
Fuel Injection ◽  
Cone Angle ◽  
Injection Rate ◽  
Effective Diameter ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Test Conditions ◽  
Needle Position ◽  
Rate Shaping ◽  
Wide Range

A prototype Diesel common rail direct-acting piezoelectric injector has been used to study the influence of fuel injection rate shaping on spray behavior (liquid phase penetration) under evaporative and non-reacting conditions. This state of the art injector allows a fully flexible control of the nozzle needle, enabling various fuel injection rates typologies under a wide range of test conditions. The tests have been performed employing a novel continuous flow test chamber that allows an accurate control on a wide range of thermodynamic test conditions (up to 1000 K and 15 MPa). The temporal evolution of the spray has been studied recording movies of the injection event with a fast camera (25 kfps) by means of the Mie scattering visualization technique. The analysis of the results showed a strong influence of needle position on the behavior of the liquid length. The needle position controls the effective pressure upstream of the nozzle holes. Higher needle lift is equivalent to higher effective pressures. According to the free-jet theory, the stabilized liquid-length depends mainly on effective diameter, spray cone-angle and fuel/air properties and does not depend on injection velocity. Therefore, higher injection pressures gives slightly lower liquid length due to small change in the spray cone-angle. However, partial needle lifts has an opposite effect: lower effective pressure upstream of the nozzle holes shows a dramatic increase on the spray cone-angle, reducing the liquid length. This behavior could be explained mainly due to the fact that the flow direction upstream of the nozzle holes is affecting the area coefficient, or in other words, the effective diameter of the holes.

Effect of Various Injection Pressures on Spray Characteristics of Karanja Oil Methyl Ester (KOME) and Diesel in a DI Diesel Engine

2015 ◽  
Vol 787 ◽  
pp. 815-819
Author(s):  
Vaibhav Prakash ◽  
B. Praveen Ramanujam ◽  
C. Sanjeev Nivedan ◽  
N. Nallusamy ◽  
P. Raghu
Keyword(s):  
Methyl Ester ◽  
Fuel Injection ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Cone Angle ◽  
Penetration Length ◽  
Spray Cone ◽  
Di Diesel Engine ◽  
Fuel Injection Pressure ◽  
Karanja Oil

The performance and emissions from diesel engines are greatly influenced by the degree of atomization of the fuel spray. The characteristics of the spray affect the physics of formation of the air-fuel mixture. They depend on density and viscosity of fuel, injection pressure, pressure and temperature of fuel. The spray structure is primarily dependent on the fuel injection pressure. This study involves the carrying out of experimental investigations on biodiesel and diesel fuel sprays in a DI diesel engine for different injection pressures. The spray cone angle and spray tip penetration length are studied experimentally. Using spray visualization system and image processing techniques, the experimental data is obtained. The fuels used are Karanja oil methyl ester (KOME) and diesel. The experimental results show that, as the injection pressure increases, the spray cone angle decreases for KOME and similar trends are observed with diesel. In addition, spray penetration length increases with increase in injection pressure and the value of the same was slightly higher for KOME than that of diesel. The results also reveal similarities in spray characteristics of both the test fuels.

Effects of nozzle geometries and needle lift on steadier string cavitation and larger spray angle in common rail diesel injector

2020 ◽  
pp. 146808742093649
Author(s):  
Zhixia He ◽  
Han Zhou ◽  
Lian Duan ◽  
Min Xu ◽  
Zhou Chen ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Cone Angle ◽  
Common Rail ◽  
Spray Angle ◽  
Injection System ◽  
Three Dimension ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Hole Position ◽  
Nozzle Hole

The cavitating flow in diesel injector nozzles plays a vital role in spray atomization and formation of fuel–air mixture, since vortex-induced string cavitation has recently been found a much more influence on spray compared to the ordinary geometry-induced film cavitation. In this study, in order to investigating string cavitation and its’ enhancement on spray, the visualization experimental platform for the real-size optical tapered-hole nozzle was built based on the high-pressure common rail fuel injection system. Groups of optical nozzles with different geometries were designed for exploring the couple effects of several nozzle geometric parameters, including nozzle sac chamber depth, nozzle-hole position height and needle lift, on the three-dimension vortex flow structure and then on the string cavitation and spray characteristics. Results indicated that the string cavitation characteristics are tightly associated with couple characteristics of the parameters. The stable and strong string cavitation during the whole injection process can be obtained in the Min-sac nozzle with the high hole position under the low needle lift. The string cavitation extends to the nozzle-hole outlet, and subsequently induces the special hollow cone spray with air in the spray center location and corresponding a larger spray cone angle even under not so high injection pressure.

Development of a High-Pressure, High-Temperature, Optically Accessible Continuous-Flow Vessel for Fuel-Injection Experiments

2013 ◽  
Author(s):  
Kemar C. James ◽  
Jin Wang ◽  
Zackery B. Morris ◽  
Michael C. Maynard ◽  
Brian T. Fisher
Keyword(s):  
Liquid Phase ◽  
Continuous Flow ◽  
High Speed ◽  
Fuel Injection ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Spray Visualization

The focus of this work was to develop a continuous-flow vessel with extensive optical access for characterization of engine-relevant fuel-injection and spray processes. The spray chamber was designed for non-reacting experiments at pressures up to 1380 kPa (200 psi) and temperatures up to 200°C. Continuous flow of inert “sweep gas” enables acquisition of large statistical data samples and thus potentially enables characterization of stochastic spray processes. A custom flange was designed to hold a common-rail diesel injector, with significant flexibility to accommodate other injectors and injector types in the future. This flexibility, combined with the continuous flow through the chamber, may enable studies of gas-turbine direct-injection spray processes in the future. Overall, the user can control and vary: injection duration, injection pressure, sweep-gas temperature, sweep-gas pressure, and sweep-gas flow rate. The user also can control frequency of replicate injections. There are four flat windows installed orthogonally on the vessel for optical access. Optical data, at present, include global spray properties such as liquid-phase fuel penetration and cone angle. These measurements are made using a high-speed spray-visualization system (up to 100 kHz) consisting of a fast-pulsed LED (light emitting diode) source and a high-speed camera. Experimental control and data acquisition have been set up and synchronized using custom LabVIEW programs. The culmination of this development effort was an initial demonstration experiment to capture high-speed spray-visualization movies of n-heptane injections to determine liquid-phase fuel penetration length (i.e., liquid length) and spray cone angle. In this initial experiment, fuel-injection pressure was ∼120 MPa (1200 bar) and the injection command-pulse duration was 800 μs. At room conditions, liquid length and nominal spray cone angle were ∼170 mm and ∼14.5°, respectively. In contrast, with air flow in the chamber at 100 psi and 100°C, liquid length was considerably shorter at ∼92 mm and spray cone angle was wider at ∼16.5°. Future experiments will include the continuation of these measurements for a wider range of conditions and fuels, extension of high-speed imaging to vapor-phase fuel penetration using schlieren imaging techniques, and detailed characterization of spray properties near the injector nozzle and near the liquid length.

Spray Characterization of Palm Olein/Diesel Blends under Various Injection Pressures

2013 ◽  
Vol 647 ◽  
pp. 645-653
Author(s):  
M.H.A.R Mantari ◽  
Y.A. Eldrainy ◽  
Mohammad Nazri Mohd Jaafar
Keyword(s):  
Diesel Fuel ◽  
Palm Olein ◽  
Cone Angle ◽  
Atmospheric Condition ◽  
Injection Pressure ◽  
Spray Angle ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Swirl Atomizer ◽  
Injection Pressures

The Sauter Mean Diameter (SMD) and spray cone angle are two important parameters that characterize spray performance. The objective of this study is to characterize palm olein/diesel blends spray in terms of spray angle and SMD under different injection pressures using a hollow cone pressure swirl atomizer. The physical properties of five diesel/palm olein blends, namely B5, B10, B15, B20 and B25 were measured and their spray characteristics were tested at injection pressures of 0.8MPa, 1.0MPa, and 1.2MPa under ambient atmospheric condition. The results were compared to spray established using petroleum diesel fuel. The SMD was measured using a phase Doppler analyzer (PDA). The spray cone angle was visualized using a digital single-lens reflex (DSLR) camera. The results indicated that petroleum diesel fuel had the widest cone angle followed by B5, B10, B15, B20 and B25 under the same injection pressure. Additionally, when the injection pressure increases from 0.8MPa to 1.2MPa, the spray cone angle widen accordingly. It is concluded that high content of palm olein in the palm biofuel blends increases viscosity and surface tension and hence higher value of SMD and narrower spray cone angle was generated. An increase in injection pressure resulted in smaller droplet SMD and wider spray cone angle.

Experimental and Numerical Studies of Diesel Spray Evaporation and Combustion in a Gas Turbine Matrix Burner

2009 ◽  
Author(s):  
Dieter Bohn ◽  
James F. Willie ◽  
Nils Ohlendorf
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Instability ◽  
Cone Angle ◽  
Spray Angle ◽  
Test Rig ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Flow Simulations ◽  
Air Inlet

Lean gas turbine combustion instability and control is currently a subject of interest for many researchers. The motivation for running gas turbines lean is to reduce NOx emissions. For this reason gas turbine combustors are being design using the Lean Premixed Prevaporized (LPP) concept. In this concept, the liquid fuel must first be atomized, vaporized and thoroughly premixed with the oxidizer before it enters the combustion chamber. One problem that is associated with running gas turbines lean and premixed is that they are prone to combustion instability. The matrix burner test rig at the Institute of Steam and Gas Turbines at the RWTH Aachen University is no exception. This matrix burner is suitable for simulating the conditions prevailing in stationary gas turbines. Till now this burner could handle only gaseous fuel injection. It is important for gas turbines in operation to be able to handle both gaseous and liquid fuels though. This paper reports the modification of this test rig in order for it to be able to handle both gaseous and liquid primary fuels. Many design issues like the number and position of injectors, the spray angle, nozzle type, droplet size distribution, etc. were considered. Starting with the determination of the spray cone angle from measurements, CFD was used in the initial design to determine the optimum position and number of injectors from cold flow simulations. This was followed by hot flow simulations to determine the dynamic behavior of the flame first without any forcing at the air inlet and with forcing at the air inlet. The effect of the forcing on the atomization is determined and discussed.

scholarly journals Experimental Study of Spray Characteristics of Kerosene-Ethanol Blends from a Pressure-Swirl Nozzle

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tao Zhang ◽  
Bo Dong ◽  
Xun Zhou ◽  
Linan Guan ◽  
Weizhong Li ◽  
...  
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Ethanol Blends ◽  
Pressure Swirl ◽  
Spray Velocity

Partial replacement of kerosene by ethanol in a gas turbine is regarded as a good way to improve the spray quality and reduce the fossil energy consumption. The present work is aimed at studying the spray characteristics of kerosene-ethanol blends discharging from a pressure-swirl nozzle. The spray cone angle, discharge coefficient, breakup length, and velocity distribution are obtained by particle image velocimetry, while droplet size is acquired by particle/droplet imaging analysis. Kerosene, E10 (10% ethanol, 90% kerosene), E20 (20% ethanol, 80% kerosene), and E30 (30% ethanol, 70% kerosene) have been considered under the injection pressure of 0.1–1 MPa. The results show that as injection pressure is increased, the discharge coefficient and breakup length decrease, while the spray cone angle, drop size, and spray velocity increase. Meanwhile, the drop size decreases and the spray velocity increases with ethanol concentration when the injection pressure is lower than 0.8 MPa. However, the spray characteristics are not affected obviously by the ethanol concentration when the injection pressure exceeds 0.8 MPa. A relation to breakup length for kerosene-ethanol blends is obtained. The findings demonstrate that the adding of ethanol into kerosene can promote atomization performance.

Impacts of duct inner diameter and standoff distance on macroscopic spray characteristics of ducted fuel injection under non-vaporizing conditions

2020 ◽  
pp. 146808742091471
Author(s):  
Feng Li ◽  
Chia-fon Lee ◽  
Ziman Wang ◽  
Yiqiang Pei ◽  
Guoxiang Lu
Keyword(s):  
Large Scale ◽  
Fuel Injection ◽  
Soot Formation ◽  
Cone Angle ◽  
Mie Scattering ◽  
Standoff Distance ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Inner Diameter

Ducted fuel injection spray is a new technology for reducing soot formation in heavy-duty diesel engines. In this work, the ducted fuel injection spray characteristics with different duct inner diameters and different standoff distances were investigated and compared with free spray. Duct inner diameter ranged from 1.5 to 4 mm, and standoff distance varied between 0.9 and 4.9 mm. Mie-scattering optical technique was used to characterize spray characteristics under various injection pressures in a constant-volume spray chamber. Ambient gas pressure of up to 6 MPa when spraying. The results showed that ducted fuel injection spray with smaller duct has better spray diffusion compared to those of ducted fuel injection sprays with larger ducts and free spray from the perspectives of spray tip penetration, spray cone angle and spray area. Increasing standoff distance could increase spray velocity. Ducted fuel injection spray with smaller duct formed a mushroom-shaped head and large-scale vortex flow close to the duct outlet. All the advantages of ducted fuel injection spray with smaller duct are interpreted as evidence of improving fuel–gas mixing quality significantly.

Characterizing Diesel Fuel Spray Cone Angle From Back-Scattered Imaging by Fitting Gaussian Profiles to Radial Spray Intensity Distributions

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Jaclyn E. Johnson ◽  
Jeffrey D. Naber ◽  
Seong-Young Lee
Keyword(s):  
Charge Density ◽  
Diesel Fuel ◽  
Curve Fitting ◽  
Cone Angle ◽  
Injection Pressure ◽  
Fuel Spray ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Gaussian Curve

Quantifying fuel spray properties including penetration, cone angle, and vaporization processes sheds light on fuel-air mixing phenomenon, which governs subsequent combustion and emissions formation in diesel engines. Accurate experimental determination of these spray properties is a challenge but imperative to validate computational fluid dynamic (CFD) models for combustion prediction. This study proposes a new threshold independent method for determination of spray cone angle when using Mie back-scattering optical diagnostics to visualize diesel sprays in an optically accessible constant volume vessel. Test conditions include the influence of charge density (17.6 and 34.9 kg/m3) at 1990 bar injection pressure, and the influence of injection pressure (990, 1370, and 1980 bar) at a charge density of 34.8 kg/m3 on diesel fuel spray formation from a multi-hole injector into nitrogen at a temperature of 100 °C. Conventional thresholding to convert an image to black and white for processing and determination of cone angle is threshold subjective. As an alternative, an image processing method was developed, which fits a Gaussian curve to the intensity distribution of the spray at radial spray cross-sections and uses the resulting parameters to define the spray edge and hence cone angle. This Gaussian curve fitting methodology is shown to provide a robust method for cone angle determination, accounting for reductions in intensity at the radial spray edge. Results are presented for non-vaporizing sprays using this Gaussian curve fitting method and compared to the conventional thresholding based method.

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