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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of ILASS-Korea
Journal Basic Information
Journal DOI :
Institute for Liquid Atomization and Spray Systems-Korea
Editor in Chief :
Volume & Issues
Volume 11, Issue 4 - Dec 2006
Volume 11, Issue 3 - Sep 2006
Volume 11, Issue 2 - Jun 2006
Volume 11, Issue 1 - Mar 2006
Selecting the target year
Production of Ultra-fine Metal Powder with Gas Atomization Processes
Wang, M. R. ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 59~68
Experimental results of the metal powder production with internal mixing, internal impinging and the atomizer coupled with substrate design are presented in this paper. In a test with internal mixing atomizer, mean powder size was decreased from
for Pb65Sn35 alloy as the gas-to-melt mass ratio was increased from 0.04 to 0.17. The particle size further reduces to
as the orifice area is increased to
. The micrograph of the metal powder indicates that very fine and spherical metal powder has been produced by this process. In a test program using the internal impinging atomizers, the mean particle size of the metal powder was decreased from
as the gas-to-melt-mass ratio increased from 0.05 to 0.22. The test results of an atomizer coupled with a substrate indicates that the deposition rate of the molten spray on the substrate is controlled by the diameter of the substrate, the height of the substrate ring and the distance of the substrate from the outlet of the atomizer. This in rum determines the powder production rate of the spraying processes. Experimental results indicate that the deposition rate of the spray forming material decreases as the distance between the substrate and the atomizer increases. For example, the deposition rate decreases from 48% to 19% as the substrate is placed at a distance from 20cm to 40cm. On the other hand, the metal powder production rate and its particle size increases as the subsrate is placed far away from the atomizer. The production of metal powder with mean particle size as low as
has been achieved, a level which is not achievable by the conventional gas atomization processes.
Study on the Characteristics of Common-rail Diesel Engine with Ultrasoniccally Irradiated Diesel Fuel
Im, S.Y. ; Jeong, Y.C. ; Cho, S.C. ; Ryu, J.I. ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 69~74
This is an experimental study on the performance characteristics and combustion characteristics of common-rail type diesel engine by using ultrasonic energy. It is carried out engine performance by engine dynamometer test and combustion characteristics using ultrasonically irradiated diesel fuel in comparison with using conventional diesel fuel. In analyzing the experiments of these results generally, these are obtained as follows. There is an affirmative effect on the side of the improvement of power and the reduction of smoke by applying the ultrasonically irradiated diesel fuel to the common rail engine. But there is less effect on the side of improvement of BSFC
Development of a New Droplet Binary Collision Model Including the Stretching Separation Regime
Ko, G.H. ; Lee, S.H. ; Roh, J.S. ; Ryou, H.S. ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 75~80
The present article proposes a new droplet collision model including the stretching separation regime and the formation of satellite droplets. The new model consists of several equations to calculate the post-collision characteristics of colliding droplets and satellite droplets. These equations are derived from the energy balance of droplets between before and after collision. For binary collision of water droplets, the new model shows good agreement with experimental data far the number of satellite droplets.
Spray Characteristics of the Rotating Fuel Injection System
Lee, D.H. ; Park, J.B. ; Choi, S.M. ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 81~88
The spray characteristics of the rotating fuel injection system were investigated. The special test rig was devised to get the spatial and momentary droplet information. This experimental apparatus consists of a high-speed motor, a shaft, a rotating fuel nozzle and an acrylic case. Spray droplet size and velocity were measured by PDPA(Phase Doppler Particle Analyzer) and instantaneous velocity field was measured by 1'IV (Particle Image Velocimetry) system. At the same time, spray visualization was performed by using ND-YAG laser-based flash photography. From these two different laser diagnostic techniques, we could get spatial and instantaneous spray information fur rotating fuel injection system. The results presented in this paper indicate that spray characteristics such as droplet size, velocity and spray pattern were strongly influenced by rotational speed.
Modeling the Influence of Gas Pressure on Droplet Impact Using a Coupled Gas/liquid Boundary Element Method
Park, Hong-Bok ; Yoon, Sam S. ; Jepsen Richard A. ; Heister Stephen D. ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 89~97
An inviscid axisymmetric model capable of predicting droplet bouncing and the detailed pre-impact motion, influenced by the ambient pressure, has been developed using boundary element method (BEM). Because most droplet impact simulations of previous studies assumed that a droplet was already in contact with the impacting substrate at the simulation start, the previous simulations could not accurately describe the effect of the gas compressed between a failing droplet and the impacting substrate. To properly account for the surrounding gas effect, an effect is made to release a droplet from a certain height. High gas pressures are computationally observed in the region between the droplet and the impact surface at instances just prior to impact. The current simulation shows that the droplet retains its spherical shape when the surface tension energy is dominant over the dissipative energy. When increasing the Weber number, the droplet surface structure is highly deformed due to the appearance of the capillary waves and, consequently, a pyramidal surface structure is formed; this phenomenon was verified with our experiment. Parametric studies using our model include the pre-impact behavior which varies as a function of the Weber number and the surrounding gas pressure.
Effective Control of fine Particles Using an Electrostatic Coagulation Between Particle and Water Droplet
Lee, Myong-Hwa ; Kim, Sang-Bum ; Hwang, You-Seong ; Kim, Jong-Ho ; Kim, Gyung-Soo ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 98~104
A charged droplet scrubber was introduced to remove visible smokes generated in many industrial facilities. Lab-scale and field tests were conducted in this study. The system consists of a corona discharger to effectively charge the fine particles, fellowed by an electrostatic chamber to promote coagulation between charged fine particles and oppositely charged droplets and a demister to remove resultant particles. Overall collection efficiency, 98.4% was obtained from a lab-scale test, when a high voltage was applied to an ionizer and a charged droplet scrubber. Field tests also show the high collection efficiencies, 93.5% with one stage and 99.4% with two stage system. This system can be used to increase the collection efficiency of the conventional air pollution control devices to satisfy the national emission standard.
A Study on the Characteristics of an Oscillating Fluidic Atomizer
Kim, K.H. ; Kiger, K. ; Lee, W. ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 105~112
A unique feature of fluidic atomizers is that the nozzle geometry produces a thin capillary Jet which is forced to oscillate on a 2-dimensional plane through the use of a passive feedback mechanism. The objective of the current work is to characterize the influence of the stagnation pressure at the nozzle exit, jet oscillation and stretching on the breakup properties of the capillary ligament. To achieve this, shadow graph technique is used to measure size, shape, velocity and the number density of the droplets as a function of the position within the spray fan. The breakup length, defined as the radial distance from the breakup point, is analyzed as a function of the non-dimensional parameters. Finally, a kinematic model is developed to simulate the breakup of the oscillating jets at low stagnation pressures. Using the existing jet breakup theories, the model is used to predict the size and diameter distribution of the droplets after primary atomization.
Spray Plume Characteristics of Liquid Jets in Subsonic Crossflows
Song, Jin-Kwan ; Ahn, Kyu-Bok ; Oh, Jeong-Seog ; Yoon, Young-Bin ;
Journal of ILASS-Korea, volume 11, issue 2, 2006, Pages 113~120
The effect of internal liquid flow on spray plume characteristics was performed experimentally in subsonic cross flows. The injector internal flow was classified as three modes such as a normal, cavitation, and hydraulic flip. The objectives of the research are to investigate the effect of internal liquid flow on the spray plume characteristics and compare the trajectory of spray plume with previous works. The results suggest that the trajectory and width of spray plume can be correlated as a function of liquid/air momentum flux ratio(q), injector diameter and normalized distance from the injector exit(x/d). It's also found that the injector internal turbulence influences the spray plume characteristics significantly.