• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.112-120
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• 2005

The injector, which is used in a 4-valve gasoline engine, is required to be maintained the dual stream because of the design of dual intake port. In addition, the spray characteristics of fuel injector have strong influence on engine performance, exhaust emission, fuel consumption, and especially the cold start condition for the port injection. So, commercial gasoline injectors off different type were inspected. Those are 2 hole,4 hole, air shroud 4 hole, and air shroud 4 hole injector with separator. The spray behavior of dual stream was researched by the visualization system and PDPA system was employed to measure the droplet size. Atomization is one of the most important characteristic, so droplet size distributions and SMD are investigated. And the spray characteristics of each injector are also analyzed such as the spray tip penetration, spray angle, and separation angle.

• International Journal of Air-Conditioning and Refrigeration
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• v.17 no.3
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• pp.94-99
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• 2009

In the Korean subway station, three types of pre-filters, which include auto filter, electrostatic precipitator (ESP) and auto cleaning demister, are widely used. However, these devices have some problems such as the difficulty of maintenance and high operating cost. In this study, axial-flow cyclone separator was employed as a pre-filter inside a heating, ventilation, and air conditioning (HVAC) system. 3-dimensional computational fluid dynamics (CFD) analysis was performed on a single unit axial-flow cyclone and coupled unit axial-flow cyclone. Calculated and measured pressure drop of the designed axial-flow cyclone were found be comparable to other types of pre-filters and the observed cut-off diameter was less than 10 micron. Considering lower operating and maintenance cost, axial-flow cyclone was proved to be a better solution as a pre-filter.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.5
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• pp.512-517
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• 2014

This paper describes the development of new sweeping machine based on Cyclone Technology, which maintains constant suction power and uses it in a industrial applications as a method for dust removed from grinding work. The performance of a cyclone separator is determined by the turbulence characteristics and particle-particle interaction. To achieve this goal, we design cyclone technology based dust separator for sweeping machine has been proposed as a system which is suitable to work utilizing dust suction alternative to conventional manual system. and Numerical analysis with computational fluid dynamics(CFD) was carried out to investigate the working fluid that flow into cyclone dust separator in order to design optimal structure of the sweeping machine. The validation of cyclone model with CFD is carried out by comparing with experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.491-498
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• 2010

Humidification of PEM fuel cells is necessary for enhancing their performance and lifetime. In this study, a humidification system was designed and tested; the system includes an air-supply tube (inner diameter: 75 mm) through which a nozzle can be directly inserted and a cyclonic separator for the removal of water droplets. Three types of nozzles were employed to study the influence of injection pressure, air flow rate, and spray direction on the humidification performance. To evaluate the humidification performance, the concept of humidification efficiency was defined. In the absence of an external heat source, latent heat for evaporation will be supplied by the own enthalpies of water and air. Thus, the amount of water sprayed from the nozzle is the most critical factor affecting the humidification efficiency. Water droplets were efficiently removed by a cyclonic separator, but re-entrainment occurred at high air flow rates. The absolute humidity and humidification efficiency were $21.29\;kJ/kg_{da}$ and 86.57%, respectively, under the following conditions: nozzle type PJ24; spray direction angle $90^{\circ}$; injection pressure 1200 kPa; air flow rate 6000 Nlpm.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.3
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• pp.305-312
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• 2011

The use of a separator to control stack temperature in a molten carbonate fuel cell was studied by numerical simulation using a computational fluid dynamics code. The stack model assumed steady-state and constant-load operation of a co-flow stack with an external reformer at atmospheric pressure. Representing a conventional cell type, separators with two flow paths, one each for the anode and cathode gas, were simulated under conditions in which the cathode gas was composed of either air and carbon dioxide (case I) or oxygen and carbon dioxide (case II). The results showed that the average cell potential in case II was higher than that in case I due to the higher partial pressures of oxygen and carbon dioxide in the cathode gas. This result indicates that the amount of heat released during the electrochemical reactions was less for case II than for case I under the same load. However, simulated results showed that the maximum stack temperature in case I was lower than that in case II due to a reduction in the total flow rate of the cathode gas. To control the stack temperature and retain a high cell potential, we proposed the use of a separator with three flow paths (case III); two flow paths for the electrodes and a path in the center of the separator for the flow of nitrogen for cooling. The simulated results for case III showed that the average cell potential was similar to that in case II, indicating that the amount of heat released in the stack was similar to that in case II, and that the maximum stack temperature was the lowest of the three cases due to the nitrogen gas flow in the center of the separator. In summary, the simulated results showed that the use of a separator with three flow paths enabled temperature control in a co-flow stack with an external reformer at atmospheric pressure.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1505-1515
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• 2009

A new method to semicontinuously determine $PM_{2.5}$ ionic species with a short time resolution is described in detail. In this system, a particle collection section (mixing part, particle collection chamber, and air/liquid separator) was developed. A Y-type connector was used to mix steam and an air sample. The particle collection chamber was constructed in the form of a helix coil and was cooled by a water circulation system. Particle size growth occurred due to the high relative humidity and water absorbed particles were efficiently collected in it. Liquid samples were drained out with a short residence time (0.08-0.1 s). The air/liquid separator was also newly designed to operate efficiently when the flow rate of the air sample was 16.7 L $min^{-1}$. For better performance, the system was optimized for particle collection efficiency with various types of test aerosols such as ($NH_4)_2SO_4,\;NaCl,\;NH_4HSO_4,\;and\;NH_4NO_3$. The particle collection efficiencies were almost 100% at different concentration levels in the range over 500 nm in diameter but 50-90% in the range of 50-500 nm under the following experimental conditions: 15 coil turns, a water flow rate for steam generation of 0.65 mL $min^{-1}$, and an air sample flow rate of 16.7 L $min^{-1}$. Finally, for atmospheric applications, chemical compositions of $PM_{2.5}$ were determined with a time resolution of 20 min on January 11-24, 2006 in Seoul, Korea, and the chemical characteristics of $PM_{2.5}$ ions were investigated.

• Membrane Journal
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• v.24 no.3
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• pp.231-239
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• 2014

Polyetherimide (PEI) membranes for separators in Zn air batteries were prepared via phase inversion process from casting solution composed of PEI, n-methylpyrolidone (NMP), and polyvinylpurrolidone (PVP). Furthermore, Zn air batteries were fabricated with the separators. The effects of PEI content and PVP addition in the casting solution on the morphology, mechanical strength, ionic conductivity were investigated through SEM, stress-strain test and ac impedance test. The elelctrochemical performances of the batteries were evaluated through galvanostatic discharge analysis. The mechanical strength of the membrane increased with increasing PEI composition in the casting solution. Little effect of PVP addition into the solution on the mechanical strength of the membrane was investigated. The ionic conductivity value decreased with increasing PEI composition in the solution. With addition of PVP, ionic conductivity of membrane increased until 10 wt% to show the maximum value of 0.1 S/cm. In the higher range of PVP addition over 10%, the ionic conductivity decreased with increasing PVP addition. Ionic conductivity of separator strongly affected the capacity of Zn air battery, and the battery assembled with the separator which showed high ionic conductivity showed high capacity.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.727-729
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• 2001

The air separation of PET (Polyethylene terephthalate) and PS(Polystyrene) was carried out by taking advantage of the different abrasive resistance of two plastics. PET bottles and PS packages were shredded to small square pieces $(5{\times}5mm)$. Both plastic shreds were treated by a shear-type crusher. The PET shreds were bent and twisted by the crush so that they were blown up easily, but the PS shreds were not. After the crush of mixture of both plastics, air separation experiments were carried out using four types of air separators. The number and location of the baffle attached to them are different. With the separator with a baffle attached at the upper part, PET recoveries for the crushing time of 30, 60 and 90sec were 67, 98 and 99% respectably at the air flow rate of 3.5m/s, whereas PS recoveries were null regardless of the crushing time.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.135-138
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• 2009

Quality evaluation of laser welded MCFC separator panels with large active area was performed. Lap joint was applied to produce stable air-tight seam weld by employing Nd:YAG laser. Results showed that surface contamination played a key role to form weld defects at the joint interface. However, there was no evidence that weld width at the lap joint changed after the stack operation time of 2,890h. Test results also revealed that the reinforcement values which were measured on the weld line after long time operation, were stable.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.599-606
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• 1995

The feasibility of foam separation to remove protein produced from fish culture water was investigated, By assuming foam separation column as a single well-mixed pool, a simplified model for foam separator conditions was alse studied under the batch operation. The model indicated that the protein removal could be described as a first-order reaction whose rate increases with both superficial air velocity and protein concentration in the bulk solution. from ,the results of an experimental study on the effects of superficial air velocity, the protein concentration, temperature, and pH on protein removal, the superficial air velocity and initial protein concentration in bulk solution were found to be important operational factors. Other experimental results important that foam separator operated under batch conditions would be considered as a completely mixed reactor. The protein removal rate by foam separation process was increased proportionally with the superficial air velocity, and the adsorptive removal rate of protein was found to obey Langmuir adsorption formula. The preposed simplified model was verified with the experimental data obtained from this study. Under the experimental range used, both temperature and pH did not affect the protein removal.