scholarly journals Optical experiments of string cavitation in diesel injector tapered nozzles

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 193-201 ◽  
Author(s):  
Genmiao Guo ◽  
Zhixia He ◽  
Xicheng Tao ◽  
Shenxin Sun ◽  
Zhen Zhou ◽  
...  
Keyword(s):  
Cone Angle ◽  
Injection Pressure ◽  
Typical Development ◽  
Type B ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Fuel Flow ◽  
Diesel Nozzle ◽  
Development Processes ◽  
Occurrence Regularity

Flow inside the diesel nozzle is crucial to spray, combustion, and emissions. This work aimed to improve the understanding of effects of internal fuel-flow on diesel spray, especially the special string cavitating flow. Optical experiments were employed for characterizing the formation of string cavitation inside the transparent scaled-up tapered diesel orifices. Simultaneously, the corresponding evolution of spray cone angles were obtained. Results show that there were two origins of the string cavitation, which were originated from inlet and outlet of the orifice, respectively. Moreover, there were two typical development processes of the string cavitation between hole and hole, which were defined as type-A and type-B string cavitation. Furthermore, effects of string cavitation were analyzed: it could trigger the geometry-induced cavitation and make a sharp increase of spray cone angle. Finally, the relationships between the occurrence regularity of string cavitation, the needle lift and the injection pressure were revealed by comparison of different needle lifts and different injection pressures.

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.

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.

Effect of Injection Parameters on the Spray Characteristics of DME Fuel

2006 ◽  
Author(s):  
Bong Woo Ryu ◽  
Seung Hwan Bang ◽  
Hyun Kyu Suh ◽  
Chang Sik Lee
Keyword(s):  
Dimethyl Ether ◽  
Diesel Fuel ◽  
Cone Angle ◽  
Injection Pressure ◽  
Injection Rate ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Injection Duration ◽  
Injection Parameters

The purpose of this study is to investigate the effect of injection parameters on the injection and spray characteristics of dimethyl ether and diesel fuel. In order to analyze the injection and spray characteristics of dimethyl ether and diesel fuel with employing high-pressure common-rail injection system, the injection characteristics such as injection delay, injection duration, and injection rate, spray cone angle and spray tip penetration was investigated by using the injection rate measuring system and the spray visualization system. In this work, the experiments of injection rate and spray visualization are performed at various injection parameters. It was found that injection quantity was decreased with the increase of injection pressure at the same energizing duration and injection pressure In the case of injection characteristics, dimethyl ether showed shorter of injection delay, longer injection duration and lower injected mass flow rate than diesel fuel in accordance with various energizing durations and injection pressures. Also, spray development of dimethyl ether had larger spray cone angle than that of diesel fuel at various injection pressures. Spray tip penetration was almost same development and tendency regardless of injection angles.

Experimental Study on Diesel Engine and Analysis the Spray Characteristics of Diesel and Biodiesel by Varying Injection Pressure

2014 ◽  
Vol 984-985 ◽  
pp. 932-937 ◽  
Author(s):  
Palani Raghu ◽  
M. Senthamil Selvan ◽  
K. Pitchandi ◽  
N. Nallusamy
Keyword(s):  
Experimental Study ◽  
Diesel Engine ◽  
Weber Number ◽  
Direct Injection ◽  
Cone Angle ◽  
Injection Pressure ◽  
Injection Velocity ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone

— The spray characteristic of the injected fuel is mainly depends upon fuel injection pressure, temperature, ambient pressure, fuel viscosity and fuel density. An experimental study was conducted to examine the effect of injection pressure on the spray was injected into direct injection (DI) diesel engine in the atmospheric condition. In Diesel engine, the window of 20 mm diameter hole and the transparent quartz glass materials were used for visualizing spray characteristics of combustion chamber at right angle triangle position. The varying Injection pressure of 180 - 240 bar and the engine was hand cranked for conducting the experiments. Spray characteristics for Jatropha oil methyl ester (JOME) and diesel were studied experimentally. Spray tip penetration and spray cone angle were measured in a combustion chamber of Direct Injection diesel engine by employing high speed Digital camera using Mie Scattering Technique and ImageJ software. The study shows the JOME gives longer spray tip penetration and smaller spray cone angle than those of diesel fuels. The Spray breakup region (Reynolds number, Weber number), Injection velocity and Sauter Mean Diameter (SMD) were determined for diesel and JOME. SMD decreases for JOME than diesel and the Injection velocity, Reynolds Number, Weber Number Increases for JOME than diesel.

Experimental study of spray characteristics of biodiesel blending with diethyl carbonate in a common rail injection system

2017 ◽  
Vol 233 (2) ◽  
pp. 249-262 ◽  
Author(s):  
Wei Fu ◽  
Lanbo Song ◽  
Tao Liu ◽  
Qizhao Lin
Keyword(s):  
Cone Angle ◽  
Injection Pressure ◽  
Injection System ◽  
Diethyl Carbonate ◽  
Spray Characteristics ◽  
Projected Area ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Common Rail Injection System ◽  
Common Rail Injection

The objective of this paper is to investigate the spray macroscopic characteristics of biodiesel, diethyl carbonate (DEC)-biodiesel blends and diesel fuel based on a common-rail injection system. The spray tip penetration, spray cone angle and the spray projected area were measured through a high-speed photography method. The experimental results reveal that injection pressure and ambient pressure have significant effects on the spray characteristics. Higher injection pressure makes the spray tip penetration increase, while higher back pressure inside the chamber leads to the enlargement of the spray cone angle. The addition of DEC causes the blends fuels to have a shorter penetration and larger spray projected area, which reveals the potential capacity to improve the atomization process compared with biodiesel. The estimation of spray droplet size indicates that DEC30 generates a smaller Sauter mean diameter (SMD) because of its lower surface tension and viscosity. Model predictions were illustrated and compared with current work.

Experimental Study on Spray Characteristics of Diesel Engines and Analysis of Fuel Dripping Phenomenon

2014 ◽  
Vol 1078 ◽  
pp. 271-275 ◽  
Author(s):  
Yu Qiang Wu ◽  
Qian Wang ◽  
Zhi Sheng Gao ◽  
Zhou Rong Zhang ◽  
Li Ming Dai
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Cone Angle ◽  
Digital Camera ◽  
Injection Pressure ◽  
Fuel Mixture ◽  
Long Distance ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone

Experimental study on macroscopic spray characteristics of a certain type of domestic common rail injectors under the conditions of different injection pressures was carried out through a high-speed digital camera. Furthermore, a fuel dripping phenomenon at the end stage of injection was observed through the high-speed digital camera equipped with a long-distance microscope, and a further analysis of the phenomenon was made. The results show the increase in the injection pressure can evidently enhance spray cone angle and expand the scope of spray field in combustion chamber, which is conducive to air-fuel mixture. The spray cone angle during the development spray shows a double-peak shape. And the long response-time of seating of solenoid valve core that disables the injection cutting off in time is one of factors causing fuel dripping phenomenon.

Experimental Study of Cavitating Flow inside Enlarged Transparent Injector Nozzles and its Effect on Spray

2014 ◽  
Vol 945-949 ◽  
pp. 935-939
Author(s):  
Yu Hang Chen ◽  
Zhi Xia He ◽  
Xiao Bin Chen ◽  
Ding Jiang
Keyword(s):  
Single Phase ◽  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Experimental System ◽  
Flow Region ◽  
Cavitating Flow ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Biodiesel Fuels

The complicated cavitating flow inside diesel nozzles has long been concentrated on. Based on the visualization experimental system, cavitating flow characteristic inside transparent nozzles with different length-diameter ratios was investigated in this paper. Experimental results showed that the cavitation is easier to occur for diesel than for biodiesel, and the longer the length of the orifice is, the harder the cavitation and hydraulic flip phenomenon to occur. Discharge coefficient of diesel was higher than that of biodiesel in single-phase flow region, while got much smaller than that of biodiesel in the cavitating flow and hydraulic flip regions.The spray cone angle of diesel was larger than biodiesel in cavitating flow regime, and got much smaller with the increasing of the length-diameter ratios under the same level of injection pressure in diesel and biodiesel fuels.

Factors Influencing the Effective Spray Cone Angle of Pressure-Swirl Atomizers

1992 ◽  
Vol 114 (1) ◽  
pp. 97-103 ◽  
Author(s):  
S. K. Chen ◽  
A. H. Lefebvre ◽  
J. Rollbuhler
Keyword(s):  
Cone Angle ◽  
Injection Pressure ◽  
Diameter Ratio ◽  
Liquid Viscosity ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Swirl Chamber ◽  
Factors Influencing ◽  
Pressure Swirl ◽  
Discharge Orifice

The spray cone angles produced by several simplex pressure-swirl nozzles are examined using three liquids whose viscosities range from 0.001 to 0.012 kg/ms (1 to 12 cp). Measurements of both the visible spray cone angle and the effective spray cone angle are carried out over wide ranges of injection pressure and for five different values of the discharge orifice length/diameter ratio. The influence of the number of swirl chamber feed slots on spray cone angle is also examined. The results show that the spray cone angle widens with increase in injection pressure but is reduced by increases in liquid viscosity and/or discharge orifice length/diameter ratio. Variation in the number of swirl chamber feed slots between one and three has little effect on the effective spray cone angle.

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