Effect of geometric and operating parameters on the spray characteristics of an open-end swirl injector

2019 ◽  
Vol 233 (12) ◽  
pp. 4457-4467 ◽  
Author(s):  
Chen Chen ◽  
Yang Yang ◽  
Xiaorong Wang ◽  
Wenxian Tang
Keyword(s):  
Pressure Drop ◽  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Operating Parameters ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Swirl Chamber ◽  
Swirl Injector

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.

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.

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 ◽  
...  
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Orifice Diameter ◽  
Hollow Cone ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Nozzle Orifice ◽  
Breakup Length

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.

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.

scholarly journals CFD simulations of the diesel jet primary atomization from a multihole injector

2017 ◽  
Author(s):  
Charalambos Chasos
Keyword(s):  
High Pressure ◽  
Nozzle Exit ◽  
Cone Angle ◽  
Injection Pressure ◽  
Liquid Jet ◽  
Spray Cone Angle ◽  
Two Phase ◽  
Spray Cone ◽  
Breakup Length ◽  
Jet Breakup

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

Experimental Study of Hydraulic Flip Phenomenon inside Diesel Nozzles Using Diesel and Biodiesel

2014 ◽  
Vol 945-949 ◽  
pp. 940-943 ◽  
Author(s):  
Zhuang Shao ◽  
Zhi Xia He ◽  
Zhi Wei Zhou ◽  
Xi Cheng Tao
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Great Influence ◽  
Flow Characteristics ◽  
Injection Pressure ◽  
Cavitating Flow ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
The Difference ◽  
Biodiesel Fuels

As cavitation inside diesel nozzles can improve the spray characteristics, it has long been a hot issue. And together with the increasing attention of biodiesel, it is essential to identify the difference of cavitating flow characteristics between diesel and biodiesel. What’s more, the hydraulic flip phenomenon and cavitating flow with decreasing injection pressure hasn’t been studied. Based on this, cavitating flow inside transparent nozzles of diesel and biodiesel fuels with increasing and decreasing injection pressure was investigated in this paper. Experimental results showed that are quite different from the disappearance of it and it is harder to disappear. Biodiesel and longer nozzle orifices were hard for the hydraulic flip phenomenon to occur, and the disappearance of hydraulic flip phenomenon has great influence on the spray cone angle and the discharge coefficient.

Jet Interaction in Liquid-Liquid Coaxial Injectors

1996 ◽  
Vol 118 (2) ◽  
pp. 329-334 ◽  
Author(s):  
D. Sivakumar ◽  
B. N. Raghunandan
Keyword(s):  
Pressure Drop ◽  
Strong Influence ◽  
Cone Angle ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Jet Interaction ◽  
Liquid Sheets ◽  
The Core ◽  
Swirl Injector ◽  
Separation Behavior

Interaction between two conical sheets of liquid formed by a coaxial swirl injector has been studied using water in the annular orifice and potassium permanganate solution in the inner orifice. Experiments using photographic techniques have been conducted to study the influence of the inner jet on outer conical sheet spray characteristics such as spray cone angle and break-up length. The core spray has a strong influence on the outer sheet when the pressure drop in the latter is low. This is attributed to the pressure variations caused by ejector effects. This paper also discusses the merging and separation behavior of the liquid sheets which exhibits hysteresis effect while injector pressure drop is varied.

Effect of Nanoparticles on the Fuel Properties and Spray Performance of Aviation Turbine Fuel

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Kumaran Kannaiyan ◽  
Kanjirakat Anoop ◽  
Reza Sadr
Keyword(s):  
Surface Tension ◽  
Physical Properties ◽  
Droplet Diameter ◽  
Cone Angle ◽  
Aviation Fuel ◽  
Alumina Nanoparticles ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Sheet Breakup

The influence of nanoparticles' dispersion on the physical properties of aviation fuel and its spray performance has been investigated in this work. To this end, the conventional Jet A-1 aviation fuel and its mixtures with alumina nanoparticles (nanofuel) at different weight concentrations are investigated. The key fuel physical properties such as density, viscosity, and surface tension that are of importance to the fuel atomization process are measured for the base fuel and nanofuels. The macroscopic spray features like spray cone angle and sheet breakup length are determined using the shadowgraph technique. The microscopic spray characteristics such as droplet diameter, droplet velocity, and their distributions are also measured by employing phase Doppler anemometry (PDA) technique. The spray performance is measured at two nozzle injection pressures of 0.3 and 0.9 MPa. The results show that with the increase in nanoparticle concentrations in the base fuel, the fuel viscosity and density increase, whereas the surface tension decreases. On the spray performance, the liquid sheet breakup length decreases with increasing nanoparticle concentrations. Furthermore, the mean droplet diameters of nanofuel are found to be lower than those of the base fuel.

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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