Characteristics of Hollow Cone Swirl Spray at Various Nozzle Orifice Diameters

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
A. Hussein ◽  
M. Hafiz ◽  
H. Rashid ◽  
A. Halim ◽  
W. Wisnoe ◽  
...  

An experimental work to investigate the swirl spray characteristics that emanates from hollow–cone and solid–cone spray simplex atomizers is presented. Main objective of the research is to investigate the spray characteristics, i.e. spray breakup length, discharge coefficient and spray cone angle at different nozzle orifice diameter and injection pressure. Discharge coefficient is almost uninfluenced by the operating Reynolds number. This test also reveals that both breakup length and spray cone angle increases as orifice diameter is increased. Higher injection pressure leads to shorter breakup length and wider spray cone angle.

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tao Zhang ◽  
Bo Dong ◽  
Xun Zhou ◽  
Linan Guan ◽  
Weizhong Li ◽  
...  

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.


Author(s):  
Chen Chen ◽  
Yang Yang ◽  
Xiaorong Wang ◽  
Wenxian Tang

To study the influence of geometric and operating parameters on the spray characteristics of an open-end swirl injector, seven injectors with different tangential inlet diameters ( D p) and injector length to injector orifice diameter ( L/D) ratios were tested and simulated. Using high-speed backlight, the evolution laws of liquid film thickness, discharge coefficient, spray cone angle, breakup length, and velocity distribution in the swirl chamber under different geometric and operating parameters were captured after unified image processing. Low-injection pressure drop is directly proportional to the discharge coefficient and the spray cone angle. When the injection pressure drop approaches or reaches a critical value of 0.4 MPa, the discharge coefficient and spray cone angle remain nearly constant with maximum fluctuations of 1% and 5%, respectively. With an increase in the geometric characteristic constant A, the liquid film thickness, discharge coefficient, breakup length, and velocity in the swirl chamber decrease, whereas the spray cone angle increases. As the viscous effect increases for increasing L/D, the discharge coefficient and breakup length increase, whereas the spray cone angle decreases. Based on experiment results, empirical formulas for the discharge coefficient, spray angle, and breakup length were put forward as reference for engineering applications, including the effect of the geometric and operating parameters.


Author(s):  
Bong Woo Ryu ◽  
Seung Hwan Bang ◽  
Hyun Kyu Suh ◽  
Chang Sik Lee

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.


2014 ◽  
Vol 984-985 ◽  
pp. 932-937 ◽  
Author(s):  
Palani Raghu ◽  
M. Senthamil Selvan ◽  
K. Pitchandi ◽  
N. Nallusamy

— 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.


Author(s):  
Wei Fu ◽  
Lanbo Song ◽  
Tao Liu ◽  
Qizhao Lin

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.


2014 ◽  
Vol 1078 ◽  
pp. 271-275 ◽  
Author(s):  
Yu Qiang Wu ◽  
Qian Wang ◽  
Zhi Sheng Gao ◽  
Zhou Rong Zhang ◽  
Li Ming Dai

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.


2014 ◽  
Vol 945-949 ◽  
pp. 935-939
Author(s):  
Yu Hang Chen ◽  
Zhi Xia He ◽  
Xiao Bin Chen ◽  
Ding Jiang

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.


2014 ◽  
Vol 1008-1009 ◽  
pp. 1001-1005 ◽  
Author(s):  
Jian Wu ◽  
Yang Hua ◽  
Zhan Cheng Wang ◽  
Li Li Zhu ◽  
Wei Wei Shang

In order to better research on the spray characteristics of biodiesel and n-butanol blends, an experimental study of spray characteristics of different fuel mixtures was investigated in a constant volume vessel using high speed photograph method, and analyzed the influence of different proportions of acidic oil biodiesel and n-butanol on the macroscopic parameters of spray penetration, spray cone angle and so on. The results show that with the increase of acidic oil biodiesel ratio, the air entrainment is weakened, spray penetration gradually increases and spray cone angle decreases under the same injection pressure and back pressure. After adding n-butanol in acidic oil biodiesel and diesel mixture fuel, the surrounding air entrainment is enhanced, and spray front end widen. With the increase of mixing ratio, spray penetration increases first, then decreases. The spray cone angle increases after adding n-butanol, and decreases with the increase of mixing ratio. The results show that adding n-butanol can be used as one of the methods to improve biodiesel spray characteristics.


Author(s):  
Charalambos Chasos

High pressure multi-hole diesel injectors are currently used in direct-injection common-rail diesel engines for the improvement of fuel injection and air/fuel mixing, and the overall engine performance. The resulting spray injection characteristics are dictated by the injector geometry and the injection conditions, as well as the ambient conditions into which the liquid is injected. The main objective of the present study was to design a high pressure multi-hole diesel injector and model the two-phase flow using the volume of fluid (VOF) method, in order to predict the initial liquid jet characteristics for various injection conditions. A computer aided design (CAD) software was employed for the design of the three-dimensional geometry of the assembly of the injector and the constant volume chamber into which the liquid jet emerges. A typical six-hole diesel injector geometry was modelled and the holes were symmetrically located around the periphery of the injector tip. The injector nozzle diameter and length were 0.2 mm and 1 mm, respectively, resulting in a ratio of nozzle orifice length over nozzle diameter L/D = 5. The commercial computational fluid dynamics (CFD) code STAR-CD was used for the generation of the computational mesh and for transient simulations with an Eulerian approach incorporating the VOF model for the two-phase flow and the Rayleigh model for the cavitation phenomenon. Three test cases for increasing injection pressure of diesel injection from the high pressure multi-hole diesel injector into high pressure and high temperature chamber conditions were investigated. From the injector simulations of the test cases, the nozzle exit velocity components were determined, along with the emerging liquid jet breakup length at the nozzle exit. Furthermore, the spray angle was estimated by the average radial displacement of the liquid jet and air mixture at the vicinity of the nozzle exit. The breakup length of the liquid jet and the spray cone angle which were determined from the simulations, were compared with the breakup length and cone angle estimated by empirical equations. From the simulations, it was found that cavitation takes place at the nozzle inlet for all the cases, and affects the fuel and air interaction at the upper area of the spray jet. Furthermore, the spray jet breakup length increases with elapsed time, and when the injection pressure increases both the breakup length and the spray cone angle increase.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.5040


2012 ◽  
Vol 225 ◽  
pp. 423-428
Author(s):  
Zulkifli Abdul Ghaffar ◽  
Ahmad Hussein Abdul Hamid ◽  
Mohd Syazwan Firdaus Mat Rashid

Injector is one of the vital devices in liquid rocket engine (LRE) as small changes in its configurations and design can result in significantly different LRE performance. Characteristics of spray such as spray cone angle, breakup length and Sauter mean diameter (SMD) are examples of crucial parameters that play the important role in the performance of liquid propellant rocket engine. Wider spray cone angle is beneficial for widespread of fuel in the combustion chamber for fast quiet ignition and a shorter breakup length provides shorter combustion chamber to be utilized and small SMD will result in fast and clean combustion. There are several mechanisms of liquid atomization such as swirling, e.g. jet swirl atomization or introducing bubbles into the liquid and effervescent atomization. Introducing a swirl component in the flow can enhance the propellant atomization and mixing whereas introducing bubbling gas directly into the liquid stream inside the injector leads to finer sprays even at lower injection pressures. This paper reviews the influence of both operating conditions and injector internal geometries towards the spray characteristics of swirl effervescent injectors. Operating conditions reviewed are injection pressure and gas-to-liquid ratio (GLR), while the injector internal geometries reviewed are limited to swirler geometry, mixing chamber diameter (dc), mixing chamber length (lc), aeration hole diameter (da), discharge orifice diameter (do) and discharge orifice length (lo).


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