• Transactions of the Korean Society of Automotive Engineers
• /
• v.6 no.5
• /
• pp.199-210
• /
• 1998

The skill that utilizes atomization of the liquid has been widely used in the field of industry and engineering. Though there are dozens of methods to make atomization, the pressure type injection nozzle is frequently used in washing of parts, pastourization and painting because it has relatively simple system. This study is to reveal the characteristics of atomizing formed by three different types of the pressure type injection nozzle. We measured velocity and diameter of droplet to compare and analyze characteristic of each nozzle. In case of velocity, atomization of hollow-cone nozzle is irregular than others and change of radial direction is especially large. Atomization of flat nozzle is nearly uniform. In case of diameter, atomization of hollow-cone nozzle is increased rapidly, as measurement point become more distant from the center of nozzle. Atomization of flat nozzle has the most fixed magnitude. Accordingly, full-cone nozzle can be used irrespective of the form of subject and hollow-cone nozzle is proper to the occasion to spray large and smooth subject. Also, flat nozzle is proper to the occasion to spray a part of subject and long groove.

• Journal of Environmental Science International
• /
• v.24 no.1
• /
• pp.73-79
• /
• 2015

The objective of this work was to treat complex mal-odor of food waste with micro-bubbles from enhanced wet scrubber system, where the pilot plant was operated. Micro bubbles from the enhanced reactor of venturi scrubber were successfully generated through the air atomizing process with high velocity more than 60 m/sec and played an important role in the removal of mal-odor. Mal-odor was effectively changed into the micro-bubble and treated with washing chemicals together. Through establishing two series connection of the reactors, 85.2 % removal efficiency of complex mal-odor was obtained in case of average 940 times of input air. 0.35 kg/hr of sulfuric acid, 0.188 kg/hr of sodium hydroxide and 0.043 kg/hr of hypochlorite were injected for chemical washing.

• Journal of Powder Materials
• /
• v.3 no.4
• /
• pp.227-232
• /
• 1996

(i) The development of a metallurgical bond during the spray forming of clad products has offered the possibility of manufacturing large rolls, including those used in hot and cold strip mills. Small rolls are already being produced in Japan. (ii) Technical developments, including the use-of-multi-atomizers have resulted in the elimination of porosity from the internal bore of a sprayed tube. Bimetallic tubing can also be manufactured and the installation of a 4.5 ton tube plant in the USA should provide low operation costs. (iii) Spray forming offers a potentially low cost manufacturing route for superalloy ring/casing components in high strength superalloys. (iv) A large pilot plant has been built for the spray forming of ultra-clean superalloys for turbine disc applications. (v) Using twin-atomizing technology, special steel billets have been spray formed up to 400mm diameter with deposition yields in excess of 90%. (vi) Al/Si alloy extrusion billets with excellent dimensional tolerances are being manufactured for large scale automotive applications. Several new aluminum alloys have also been developed, including high strength, low density and low cocfficient of expansion materials. (vii) New copper alloys have been developed and pilot plants are in operation to produce these alloys once markets have become established.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.10a
• /
• pp.173-178
• /
• 2003

The study was performed to understand combustion characteristics of the slinger combustor. Liquid fuel is discharged radially outwards through injection holes drilled in the high speed rotating shaft. We observed atomizing characteristics with variation of fuel nozzle rotating speed by using PDPA system. The mean drop diameter highly depends on fuel nozzle rotating speed. In KARI combustion test facility, Ignition and combustion tests were performed by using real scale combustor. In the test results, ignition and combustion efficiency were increased according to increasing fuel nozzle rotating speed. The measured radial temperature distribution at the combustor exit shows stable and fairly good distribution.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.119-122
• /
• 2009

The purpose of this study is to design of film-cooling ring for the small thrust rocket engine using green propellants(Hydrogen peroxide and kerosene). Cold flow test was carried out to measure the mass flow rate and atomizing characteristic. Required mass flow rate was obtained from thermal analysis of the engine, and measured flow rate 42.25g/s was in the range of permissible coolant flow rate. With the same mass flow rate, cooling ring with more hole and high velocity shows better spray pattern. The result of thermal analysis, cooling ring has enough cooling performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2007.11a
• /
• pp.381-386
• /
• 2007

Jet-A spray, evaporation and combustion were numerically analyzed in annular type model combustor using KIVA-3V. Liquid fuel's atomizing was affected by flow field near droplet. When cooling flow was not optimized, SMD was increased, and equivalence ratio was horizontally distributed in combustor's downstream. Flame spread out horizontally and separated in combustors downstream. Flame center was separated by cooling flow. Flame separation made local high temperature in downstream that caused NO increase.

• Journal of the Korean Society of Visualization
• /
• v.12 no.2
• /
• pp.9-12
• /
• 2014

Conventional electrospray and air spray methods have the vulnerabilities of limited flow rate (throughput) and droplet size, respectively. Since high throughput with uniform size of droplet is required for various applications, an improved technique should be adopted. Here, we report a combined system of an air pressure and an electric field and evaluate the atomization performance of it. The air flow allowed applying high flow rate range and the electric field reinforced the atomization process to generate fine droplets. A correlation between two forces was investigated by comparing the droplet produced by each method. The atomized droplets were measured and visualized by image processing and a particle image velocimetry (PIV). The quantitative results were achieved from the parametric space and the effect of both forces was analyzed. The motion of charged droplets followed the outer electric field rather than the complex vortex in the shear layer so that the droplets accelerated directly toward the grounded collector.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.8
• /
• pp.1056-1067
• /
• 1997

Present study visualized flow pattern and investigated spray characteristics of twin-fluid atomization with converging-diverging nozzles. Particle sizes were measured by using the Malvern particle analyzer, and the radial size distributions were evaluated by using the tomographic transform technique. The results show that the SMD generally increases in the radial direction at a prescribed liquid flow rate and the increasing rate in the SMD becomes gradual as atomizing gas pressure increases. The SMD decreases as the liquid flow rate increases at a fixed GLR (gas/liquid mass ratio). The atomization performance of the protrusion-type nozzle turned out to be superior to that of the flush-type. However, in the case of the protrusion-type, flow separation occurs outside the liquid delivery tube when the pressure at the gas nozzle chamber is high enough, which may deteriorate the atomization performance.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.2
• /
• pp.697-709
• /
• 1996

Supersonic axisymmetric jets issuing from various kinds of nozzles with a throat diameter of a few millimeters were experimentally investigated. The exit Mach number and Reynolds number based on the throat diameter of nozzle were in the range of 1.0 ~ 5.9 and 8.4$\times$ $10^4$ ~ 2.9$\times$$10^6$, respectively. The nozzle pressure ratio was varied from 5 to 85. Present paper aims to offer fundamental information of the supersonic free-jets, with an emphasis to give data with which the shape of the free-jets can be depicted under a specified condition. Experimental data are summarized to enable an estimation of the shape of the supersonic free-jets. The result shows that the shape of free-jets is dependent on only the nozzle pressure ratio.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.12
• /
• pp.1591-1599
• /
• 2004

A series of experiments were conducted to study the effectiveness of the extinction of a liquid pool fire with two different water atomizing nozzles. Fire source is a small-scale circular stainless steel pan of 120mm in diameter with the fuels of hexane and ethanol. K-type thermocouples were used to measure the flame and fuel temperature along the pool centerline and under fuel surface. A digital camera was used to visualize the process of the fire suppression. The experimental results show that water mist droplet size is l15∼180${\mu}{\textrm}{m}$ with nozzle A and 130∼190${\mu}{\textrm}{m}$ with nozzle B. The extinguishing time of pool fire was reduced with the increase of pressure. When water droplets are small, they do not reach the flame base since they may be deflected or evaporated by the fire plume. However, influence of flow rate is more important than droplet size on fire extinction. Among the fire extinction mechanisms, drop of flame temperature is superior to suffocation of $O_2$ concentration.