• Journal of ILASS-Korea
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• v.11 no.1
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• pp.24-29
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• 2006

Spray characteristics produced by conventional and electrostatic pressure-swirl nozzles for an oil burner have been studied, using kerosine as a test liquid. The charge injection mechanism is used to design the electrostatic nozzle, where specific charge density, breakup length, spray angle and mean diameter are measured and analyzed. Three nozzles with orifice diameters of 0.256, 0.308 and 0.333mm at injection pressures of 0.7, 0.9, 1.1 and 1.3 MPa are used in the study. In case of the electrostatic nozzle, voltages ranging from -5 to -12kV are applied. Comparison of the spray characteristics is made between the conventional and electrostatic nozzles. The results showed that, the electrostatic nozzle is superior to the conventional nozzle. This is due the effect of voltage on the liquid surface tension.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.11
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• pp.1552-1560
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• 2001

This paper presents the experimental results of a study undertaken to develop an electrostatic spray system for a combustion application. The characteristics of the liquid atomization and the droplet dispersion in the electrostatic spray of twin fluids were investigated by the optical measurement techniques. The processes associated with the break-up of charged jets were also observed using the laser sheet visualization. The diameter and velocity of droplets were simultaneously measured using the phase Doppler measurement technique. The electrostatic atomization of the liquid fuel depended primarily on the charging voltage and the flow rate, but the dispersion of droplets depended significantly on the aerodynamic flow. Aerodynamic influences on the liquid atomization decreased with an increase of the charging voltage. Consequently, the liquid atomization and the droplet dispersion could be independently controlled using the electrostatic and aerodynamic mechanisms.

• Journal of ILASS-Korea
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• v.11 no.1
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• pp.7-16
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• 2006

Performance of thin films fabricated with the electrostatic spray deposition (ESD) technique is strongly governed by surface morphology, which depends on deposition parameters such as deposition time and temperature, solution properties, and surface characteristics of substrates. In this article, the state of the art on the relationships between the surface morphology and the deposition parameters is presented. Also studies on the electro-hydrodynamic atomization process and the motion of drops relevant to the ESD technique are briefly reviewed, and the future research works are suggested.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.2053-2065
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• 2003

The current trend in automotive finishing industry is to use more electrostatic rotating bell (ESRB) need space to their higher transfer efficiency. The flow physics related with the transfer efficiency is strongly influenced by operating parameters. In order to improve their high transfer efficiency without compromising the coating quality, a better understanding is necessary to the ESRB application of metallic basecoat painting for the automobile exterior. This paper presents the results from experimental investigation of the ESRB spray to apply water-borne painting. The visualization, the droplet size, and velocity measurements of the spray flow were conducted under the operating conditions such as liquid flow rate, shaping airflow rate, bell rotational speed, and electrostatic voltage setting. The optical techniques used in here were a microscopic and light sheet visualization by a copper vapor laser, and a phase Doppler particle analyzer (PDPA) system. Water was used as paint surrogate for simplicity. The results show that the bell rotating speed is the most important influencing parameter for atomization processes. Liquid flow rate and shaping airflow rate significantly influence the spray structure. Based on the microscopic visualization, the atomization process occurs in ligament breakup mode, which is one of three atomization modes in rotating atomizer. In the spray transport zone, droplets tend to distribute according to size with the larger drops on the outer periphery of spray. In addition, the results of present study provide detailed information on the paint spray structure and transfer processes.

• Journal of Biosystems Engineering
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• v.29 no.1
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• pp.21-28
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• 2004

Spraying is one of the most efficient methods for pesticide and insecticide control. Generally, orchard sprayers(aircarrier sprayer) are used for such applications. However, when an orchard sprayer is used, only 20% of total amount of spray deposits on the target. The rest of spray are not only wasted but are also potential sources of environmental pollution. The research far the development of electrostatic spraying system for orchard sprayer was conducted to develop the new pesticide application technology for the reduction of environmental pollution and f3r the production of safe agricultural products. The spray characteristics for nozzles with the different charging methods were tested and the effect of electrostatic charge was analyzed, in the laboratory experiments. The results of this study indicate that the capacitive type of electrostatic spraying nozzle exhibits a large current deposition of water sprays on the sample target. The covering area ratio by conventional spraying system was 10.2%, while that of electrostatic sprays with pulse induction charging method gave the increased covering area ratio by 4.3 times.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.37.2-37.2
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• 2010

Electrostatic spray deposition is an innovative coating technique that produces fine, uniform, self-dispersive (due to the Coulombic repulsion), and highly wettable, atomized drops. Copper-indium salts are dissolved in an alcohol-based solvent, which is then electrostatically sprayed onto a moderately heated, molybdenum-coated substrate. Solvent flowrates range from 0.02 to 5 ml/hr under applied voltages of 1 to 20 kV yielding drop sizes around a few hundred nanometers. By comparing the scanning electron miscrscope images of coated samples, the substrate temperature, applied voltage, solvent flowrate, and nozzle-substrate distance are demonstrated to be the primary parameters controlling coating quality. Also, the most stable electrostatic spray mode that reliably produces uniform and fine drops is the cone-jet mode with a Taylor cone issuing from the nozzle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.401-402
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• 2010

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.16-23
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• 2002

Electrostatic pressure-swirl nozzle for practical oil burner application has been designed. The charge injection method has been used in this design, where the nozzle consists of a sharp pointed tungsten wire as a charge injector and the nozzle body grounded. The spray characteristics of the nozzles have been investigated by using an insulating liquid, i.e. kerosene without active surface agent. Breakup length of liquid decreased with an increase in applied voltage and injection pressure, while the spray angle increased with an increased in both applied voltage and injection pressure. An empirical equations have been suggested to predict the breakup length for electrostatic pressure-swirl atomizer. The experimental result was within the range of the predicted equations. The SMD decreased between the ranges of 2.8 ${\sim}$ 33% when the conventional nozzle was compared to the electrostatic with -10 kV applied to the electrode at a radial distance from 5 to 20 mm.

• Plant Journal
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• v.16 no.1
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• pp.34-37
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• 2020

The need to improve the performance of the dust collector by increasing the fine dust pollution in Korea is eminent. In this study, electrostatic spray wet electrostatic precipitator is used to remove Particulate Matter (PM). In order to enter the Cone-jet mode, which is the most stable spray mode among the various modes of electrostatic spraying, an appropriate voltage-flow condition must be satisfied, and a voltage-flow interval enabling this can be expressed as Stability Island. The voltage at which the conduit mode starts in the Stability Island section is referred to as the electrostatic spray minimum voltage (Onset Voltage). However, the conventional electrostatic spray is uses a very low flowrate, at most few millilitres per minute. The use of much higher flowrates has introduced different patterns of electrospray modes. In this study, the different spray modes will be studied in detail.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.8
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• pp.1111-1120
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• 1998

Spray Drying Absorber(SDA) system, where the combustion product gas is mixed with atomized limestone-slurry droplets and then the chemical reaction of $SO_2$ with alkaline components of the liquid droplets forms sulfates, has been widely used to eliminate $SO_2$ gas from coal fired power plants and waste incinerators. Liquid atomization is necessary because it can maximize the reaction efficiency by increasing the total surface area and dispersion angle of the alkaline components. First, numerical calculations using FLUENT are carried out to investigate $SO_2$ concentration distribution and thus to calculate $SO_2$ removal efficiency. So to attain the optimized spray conditions, then an electrostatic spraying system is set up and spray visualization is performed to show the effect of an electric field on overall droplet size. Next, the effect of an electric field on the concentrations of $SO_2$ is experimentally examined. Field strength is varied from -10 kV to 10 kV and configurations of conduction charging and induction charging are utilized. Consequently, the electrostatic removal efficiency of 501 increases about 30% with the applied voltage of ${\pm}10kV$ but is independent of polarity of the applied voltage. It Is also found that the conduction charging configuration results in higher efficiency of $SO_2$ removal that the induction charging configuration. Finally, the effect of slurry temperature on $SO_2$ removal is studied. The temperature influences on the electrostatic removal efficiency of $SO_2$.