• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4334-4340
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• 2012

In this work, we developed and evaluated the Liquid Particle Generator for generating fine particles in the air. The Liquid Particle Generator, which was based on the spray-evaporation method, had two kinds of orifices: 0.3 mm and 0.5 mm. The Liquid Particle Generator was operated at different pressure between 1 bar and 4 bars to find relationship between input pressure and droplet output rate. In addition, the size distribution of the droplets generated by the Liquid Particle Generator with different orifices was measured by the SMPS system and the optical particle counter. As a result, it was shown that the Liquid Particle Generator with 0.3 mm orifice generated droplets of around 0.3 ${\mu}m$ and atomized particles very stably. The Liquid Particle Generator having 0.5 mm orifice generated bigger droplets, compared with the Liquid Particle Generator with 0.3 mm orifice. Additionally, in these Liquid Particle Generators (0.3 mm and 0.5 mm orifice), little coagulation of particles did occur because of fine droplets atomized by the jet. Therefore, the Liquid Particle Generator could be used as an aerosol generator for atomizing fine particles.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.4
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• pp.797-808
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• 2001

Three-dimensional trajectory of fluid particle is simulated by a particle motion, which is able to examine the influences of changes in the several parameters. To calculate the trajectory of a particle, the Runge-Kutta method was utilized. The use of a projectile of particles for the trajectory of liquid jet has been shown to be useful to estimate the influence of different operating parameters such as best particle diameter, density of liquid body, initial take-off velocity, wind velocity, cross wind velocity, take-off angle, and base angle for a released flow from the nozzle. The results give the trajectories of various types of particle of body and at different elevations, base angles, wind velocities and densities of liquid body. The trajectories in a vacuum show that air resistances decreases both the distance and the maximum height of a projectile, and also explain that the termination time is also reduced in air. In addition, the maximum distance in the x direction was obtained with take-off angles from 30 degrees to 45 degrees in still air and the projectile of particles was highly effected by wind and cross wind. Clearly, a particle has to be so positioned as to take the optimum possible advantage of the wind if the maximum distances is requested. The wind astern increased the maximum distances of x direction compared with the wind ahead. Finally, it is possible to optimize the design of pump by using these results.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.2
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• pp.124-131
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• 1993

Recently. with the rapid development in large sea water systems. there occurs much interest in the study of erosion-corrosion. In this study. the mild steel(SB41) was tested by using of a erosion-corrosion test apparatus with fountain-jet and was investigated under the environments of liquid, air-liquid 2 phase flow and solid particle-liquid 2 phase flow. Main results obtained are as follows : 1. The weight loss by corrosion-erosion in air-liquid 2 phase flow are more increased than that in only liquid solution. 2. Effect of air-liquid 2 phase flow on corrosion-erosion sensitivity becomes more sensitive in natural seawater than that in distilled water. 3. The corrosion potential by corrosion-erosion in air-liquid and solid particle-liquid 2 phase flow becomes noble than that of only liquid solution.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.371-377
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• 2014

Characteristics of holdup and flow behavior of fluidized solid particles were investigated in a liquid-solid circulating fluidized bed ($0.102m{\times}3.5m$). Effects of liquid velocity ($U_L$), particle size ($d_P$) and solid circulation rate ($G_S$) on the solid holdup, overall particle rising velocity, slip velocity between liquid and particles and hydrodynamic energy dissipation rate in the riser were examined. The particle holdup increased with increasing $d_P$ or $G_S$ but decreased with increasing $U_L$. The overall particle rising velocity increased with increasing $U_L$ or $G_S$ but decreased with increasing $d_P$. The slip velocity increased with increasing $U_L$ or $d_P$ but did not change considerably with $G_S$. The energy dissipation rate, which was found to be closely related to the contacting frequency of micro eddies, increased with increasing $d_P$, $G_S$ or $U_L$. The solid particle holdup was well correlated with operating variables such as $U_L$, $d_P$ and $G_S$.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1308-1315
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• 1998

Effects of particle size of alumina on densification behavior during liquid-phase sintering of alumina-talc system were investigated with emphasis on particle rearrangement process. In the case of using coarse alu-mina powder densiication of specimens was rapidly accelerated after formation of liquid phase due to easy particle rearrangement process with addition of talc and increase of sintering temperature. On the contrary when fine alumina powder was used premature densification of alumina matrix region formed before for-mation of liquid phase rigid skeleton structure and then it seemed to inhibit rearrangement process during crease of sintering temperature. As results the densification of specimens using coarse alumina powder was higher than that of the case of using fine one.

• Journal of Information Display
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• v.3 no.3
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• pp.17-23
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• 2002

In this work we report methods of formation of three-dimensional structures of particles in a liquid crystal host. We found that, under the appropriate conditions, the particles are captured and dragged by the moving isotropic/nematic front during the phase transition process. This movement of the particles can be enhanced significantly or suppressed drastically with the influence of an electric field and/or with changing the conditions of the phase transition, such as the rate of cooling. As a result, a wide variety of particle structures can be obtained ranging from a fine-grained cellular structure to stripes of varying periods to a course-grained "root" structures. Changing the properties of the materials, such as the size and density of the particles and the surface anchoring of the liquid crystal at the particle surface, can also be used to control the morphology of the three-dimensional particle network and adjust the physical properties of the resulting dispersions. These particle structures may be used to affect the performance of LCD's much as polymers have been used in the past.

• Particle and aerosol research
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• v.11 no.4
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• pp.99-105
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• 2015

The possible existence forms of particle aggregates in liquid medium are classified into four different types according to their morphological characteristics, including the single particles that are separated from each other, the linear aggregates in which all component particles are located in a line, the planar aggregates where all particles are arranged on a plane, and the volumetric aggregates where all particles forms a three-dimensional space. These particle aggregates with different space morphologies have different fractal dimensions and different influence on the rheological phenomena of the solid-liquid system. The effects of various aggregates on the suspension viscosity are analyzed and related with the particle concentration, and then a mathematical model is presented to determine the fractal dimensions of various aggregates by measuring the apparent viscosity of the solid-liquid system. In the model, the viscous fractal dimension is developed as a new concept, the fractal dimensions of different aggregates can be obtained separately and then the relative components of various aggregates experimentally analyzed.

• International Journal of Fluid Machinery and Systems
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• v.7 no.2
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• pp.54-59
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• 2014

Particle Image Velocimetry combined with developed image processing method is adopted to study the liquid-solid two phase flow in the centrifugal pump impeller with crystallization phenomenon. The tracer particle is used to follow the liquid phase, which has the diameter between 8 to $12{\mu}m$. The crystal particle precipitates from the sodium sulfate solution does change the wavelength of the laser, and which has great laser scattering characteristics. The diameter of the crystal particle is larger than $20{\mu}m$. Through calculating the diameter of the particles in the image, the tracer particle and the crystal particle can be distinguished. By analyzing the experimental result, the following conclusion has been obtained. During the delay period, there is not any crystal particle and the pump performance has not been changed. As the crystallization process begins, the crystal nuclei appears from the supersaturation solution and grows larger with temperature decreasing, which has the tendency of moving towards the pressure side. The characteristics of liquid-solid two phase flow with crystallization phenomenon in the pump are obtained according to analysis of experimental results, and some guiding advices are presented to mitigate the crystallization phenomenon in pump impeller.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.570-577
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• 2002

Charged liquid particle's behavior in electric and flow field was simulated to define the effect of electric field on the contact area and its dispersion. For the simulation of flow and electric field finite volume method was applied. To find out the particle's moving path in that field lagrangian equation of motion was solved by Runge-Kutta methods. We assumed that the particle was charged 10% of Rayleigh limit while the particle passing through the electrode and the particle does not have an effect on the electric field. In case of 30[Kv] of voltage charging the particles injected from the central 60% of the nozzle injection area adhere to the grounded moving plate and no dispersion occurred. Increasing the charged voltage to 40[Kv], it brought about the same phenomena as that of 30[Kv] charging except the dispersion. Voltage increasing from 30[Kv] to 40 [Kv] caused higher Coulomb force acts on the particle and it made the particle dispersion.

• Particle and aerosol research
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• v.8 no.1
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• pp.37-43
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• 2012

In this study, we designed a 'spark in liquid' system. The spark discharge between two electrodes were used to generate particles by using sufficient temperature to evaporate a part of electrodes. The power supply system provides a continuous spark discharge by discharging of the capacitor to ionize the electrodes in liquid. The DC spark discharge system operates with 1-10 kV voltage. Processed copper and graphite rods were used to both electrodes with 1-3 mm diameter. There are several variables which can control the particle size and concentration such as gap distance between electrodes, applied voltage, operating liquid temperature, electrode type and liquid type. So we controlled these variables to confirm the change of particle size distribution and concentration of particles contained in liquid as wt%. 'spark in liquid' system is expected to apply nanoink by control of concentration with analysis of characteristics.