• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.921-927
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• 1996

The purpose of this study is to compute the stress intensity factors of various conditions in the cracked p! ate. The stress intensity factor of pin-loaded cracked plate is investigated using the finite element method. This paper is divided into the two parts. The first part is the contact analysis, and the second is to compute the stress intensity factors. In the contact analysis, the iterative method is used, and convergence of this method is presented. In the computation of the stress intensity factors of plate, the length of crack, clearance, and angle are considered

• Journal of computational fluids engineering
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• v.21 no.3
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• pp.98-109
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• 2016

The flow and heat transfer characteristics of a heat exchanger having rectangular pin-fin in the flow direction have been investigated numerically. On the bottom plate, the convective boundary conditions for the hot side was given, and the fins were arranged in a channel-type geometric model using the periodic boundary condition in the span-wise direction. Three-dimensional numerical calculations for the flow and conjugate heat transfer problem were conducted using SIMPLE algorithm and $k-{\varepsilon}$ turbulence model. For the slanted pin-fin models, it was found that the downward cooling flow is generated due to the downward pressure gradient component, which can enhance the heat transfer performance near the bottom surface and the fin stem region. Four different inclined angles were considered in the Reynolds number range of 13,500-55,000. The aero-thermal performance of the slanted pin-fin heat exchangers, such as the volume and area goodness factors, were summarized and compared with the baseline plate-fin type heat exchanger quantitatively.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.91-91
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.85-85
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• 2007

• Particle and aerosol research
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• v.14 no.4
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• pp.121-133
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• 2018

In this study, we developed a flat-plate type wet electrostatic precipitator that generates stable corona discharge compared to wire type discharge electrode. In order to compare the particle removal efficiency according to the shape of the discharge electrode such as the variation of the horizontal and vertical distance between spiked edges, and the variation of the height of discharge pin support were tested. As a result, when the horizontal distance between spiked edges was increased up to 36 mm, the vertical distance between spiked edges was increased up to 54 mm, and the height of the discharge pin support was increased up to 76 mm, the removal efficiency of PM10 was maintained at approximate 60.0%. Furthermore, the removal efficiency of particles over $5{\mu}m$ was about 80% or more. When the flow rate was 4 m/s, the gap between collection plates was 60 mm, and -14 kV was applied to the discharge electrode. The particle removal efficiency of the flat-plate type electrostatic precipitator was maintained when the horizontal and vertical distance between spiked edges, and the height of the discharge pin support was below a certain level. Those variables may be the important design factors for the shape of the discharge electrode. Therefore, when designing the electrostatic precipitator with multiple channels, the horizontal and vertical distance between spiked edges, and the height of discharge pin support must be selected in consideration of the weight of the discharge electrode and the processing cost.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.8 s.227
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• pp.961-967
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• 2004

An inclined jet impinging on a pin fin heat sink is proposed and investigated experimentally. To investigate the flow pattern, flow visualization using fluorescence and velocity measurement using particle image velocimetry(PIV) are conducted with water. The jet impinges over a wide span of the heat sink with a large recirculation in the upper free space and occasionally with another smaller one in the upstream corner. Further, thermal experimentation is conducted using air to obtain temperature profiles using a thermocouple rake in the air and using thermal image on the heat sink back plate, with impinging angles of 35, 45 and 55 degrees. The Reynolds number range based on the nozzle slot is varied from 1507 to 6405. The results show that impinging angle of 55 degree shows the largest heat transfer capability. The results of thermal experiment are compared and discussed with those of flow visualization.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1262-1265
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• 2004

A cycloidal speed reducer is a type of the speed reducers of machinery. The cycloidal speed reducer consists of two cycloidal plate gears, housing roller gear, input shaft, output pin and shaft, and eccentric bearings. Especially the cycloidal plate gear has the peculiar parts of the teeth, because of gearing with the housing roller gear that has the several rollers on the circular line. And then all teeth on the cycloidal plate gear can be designed to contact with the rollers on the housing roller gear at the same time. Therefore the cycloidal plate gear has always contact motion with rollers and the force is interacted between roller gear with cycloidal plate gear. Because the contact force and friction force must be required to improve the accuracy in design procedures of cycloidal speed reducers, this paper presents a force analysis considered friction effect approach derived by static force equilibrium condition, geometrical adaptation, instant velocity center method and relative velocity method.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.249-261
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• 1997

A basic study on the lifting lug design has performed through the rational and systematic process. In order to evaluate the proper design-load distribution around lug eye investigation of contact force between lifting lug and shackle pin is performed using non-linear parametric analysis idealized by gap element models. Gap element modeling and nonlinear analysis procedures are illustrated and discussed based on MSC/NASTRAN. Some analysis and design guides are suggested through the consideration of several important effects such as stress distribution pattern, circumferential contact force distribution along the lug eye face, loading share rate between lug main plate and doubler, effect of loading direction, relation between applied force and deflection and size effect of shackle pin radius. Additionally optimum design studies are performed and general trends according to the variation of design parameters are suggested.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.500-507
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• 2008

By Using various grinding mill in powder cosmetics manufacturing process; screen milt and pin mill, jet mill, properties of the powder and grinding mills were studied; talc, mica, nylon powder, silica, titanium dioxide. Besides, the experiments fur evaluation of grinding were performed by using iron oxides those are tracers. In powders of plate shape, they were grinded more vertically than horizontally at the screen mill and pin mill, although were all grinded vertically and horizontally at the jet mill. The spheric powders became the primary particles or aggregation by electrostatic interaction at the screen mill and pin mill. But, at the jet mill, they resulted the agglomeration or transformation or damage up to 2bar. Titanium dioxides became the primary particles by all grinding mill. Pin mill has an excellent result in experiments which is a change of the tone of color by grinding. From these results, suggest that the jet mill is used to pre-treat of powders of plate shape in practical cosmetic manufacturing process, and the screen mill and pin mill are used to match the color of powder cosmetics. If industrial process condition is taken into consideration, suggest that 4times of grinding is excellent on grinding effect by the screen mill, and twice grinding by the pin mill and grind air pressure of 1bar by the jet mill.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.10
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• pp.939-946
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• 2001

This study investigates the electrical and collection characteristics of a wide plate spacing electrostatic precipitator (ESP), using a pilot-scale one. Electrical operating characteristics and collection efficiency were measured for various shapes of discharge electrodes. The collection plate spacing ranged from 300 to 550 mm. Results of electrical characteristic and collection efficiency tests as a function of collection plate spacing, discharge electrode type, applied voltage, and particle diameter were obtained. Increasing the collection plate pitch and altering the corona electrode geometry was found to increase the collection efficiencies without increasing input power requirement. The best efficiency is achieved for the discharge electrode of twisted pin type.