• 한국기계가공학회지
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• 제10권3호
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• pp.67-72
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• 2011

Turbine blades operate under high temperature and pressure. The influence changes according to its width and angle. Thermal stress and pressure are important factors to analyze the stress distribution. The purpose of this study is to investigate the effects of loads on the gas turbine blade using thermal stress analysis. These analysis results show the gas fluid flow with a high pressure around the surface of blade. Gas temperature is related to the pressure of flow around the blade. The stress concentration around blade is shown and the concentration is due to the difference between suction side and pressure side of combustion gas.

• 한국자동차공학회논문집
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• 제12권3호
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• pp.152-158
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• 2004

An experimental study was performed to determine the fin-side heat transfer and pressure drop of a condenser for automobile. Five sample with different fin height and louver angle were tested, 9mm, 8mm, 7.5mm, 5.4mm and 4.5mm. Results are presented as plot of Colburn j-factor(or heat transfer coefficients) and friction factor(or pressure drop) against the Reynolds number(or inlet air velocity) based on louver pitch, in the range of 110 to 480. The results show that both heat transfer and pressure drop on the fin are mainly affected by the louver angle in a lower range of air velocity, but, by the fin height in a higher range of air velocity. The performance of 5.4mm fin is the highest, compared to other fin sample.

• 한국공작기계학회논문집
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• 제15권2호
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• pp.38-43
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• 2006

A turbine blade operates under high temperature, high pressure, and the loads have the characteristics that the amplitudes change. Therefore, it is important to perform a stress analysis considering thermal and pressure loads. The purpose of this study is to investigate the effects of these loads on gas turbine blade through thermal stress analysis. The analysis results shows that pressure in gas fluid flow around blade is high in leading edge part, Gas temperature is connections with pressure of flow around blade. The distribution of stress from blade is appearing as is different at suction side and pressure side.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.25-30
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• 2000

Plate and shell heat exchanger(P&SHE) has been applied to the refrigeration and air conditioning systems as evaporators or condensers fur their high efficiency and compactness. The purpose of this study is to analyze the characteristics of pressure drop in plate and shell heat exchanger. An experiment for single phase (low pressure drop in plate and shell heat exchanger was performed. Also numerical work was conducted using the FLUENT code for $ {\kappa}-{\varepsilon}$ model. The dependence of friction factor on geometrical Parameters was numerically investigated. The study examines the internal flow and the pressure distribution in the channel of plate and shell heat exchanger. The results of CFD analysis compared with experimental data, and the difference of frictor factor in plate side and shell side are 10% and 12%, respectively. Therefore, the CFD analysis model is effectively predict the performance of plate and shell heat exchanger.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.117-124
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• 2007

The pressure ripple in most hydraulic systems is the root cause of their noise and vibration. This paper reduced the pressure ripple using side branch hose for an axial piston pump applied to small excavator. First, in calculating open area, a new method using groove area of valve plate is proposed. Simulation model in AMESim environment is developed to verify proposed method, find effective length and diameter of branch hose. Finally, the comparisons with experiment results show that the proposed method is more effective than previous method in reducing the pressure ripple.

• 한국추진공학회지
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• 제24권1호
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• pp.47-57
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• 2020

1단 베인 엔드월에서 막냉각 성능을 증가시키기 위해서 본 연구를 진행하였다. 1단 베인에서의 유동 및 막냉각 특성을 분석하기 위해 수치해석을 진행하였고, 유동특성을 고려하여 서로다른 6가지의 막냉각 홀 배열을 설계하였다. 그 결과, 기본형상의 경우 냉각유체가 흡입면으로 편향되면서 압력면과 노즐 목에서 낮은 냉각 효율을 나타냈다. 반면 일부 홀들을 압력면을 따라 설치한 경우, 횡방향 유동이 냉각유체에 미치는 영향이 감소하여 압력면과 노즐 목에서 막냉각 효율이 증가하였다. 이에 기존 막냉각 홀 배열보다 막냉각 효율이 16% 증가하였다.

• 복식문화연구
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• 제10권2호
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• pp.178-185
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• 2002

The purpose of this study was to measure distribution of clothing pressure on breast in brassiere according to body shape and motion, and the position of hook-and-eye on brassiere, and to get basic data for comfortable brassiere design. Clothing pressure was measured from 8 female subjects under wearing trials in climatic chamber. When brassiere was tied together with inner or outer hook-and-eye, clothing pressure under the condition were 10.2 and 9.6 gf/cm², respectively. With the degree between main body and arms increased from 0° to 45° and 90°to the front, clothing pressure decreased from 10.2 to 9.6 gf/cm², and then increased to 10.4 gf/cm² When the decree was increased from 45° to 70° to the flank, the pressure increased from 9.3 to 10.6 gf/cm². Fat body shape recorded 10.8 gf/cm², and lean body shape recorded 9.5 gf/cm² of clothing pressure by wearing brassiere. Clothing pressures of brassiere were 7.8g gf/cm² in front, 9.5 gf/cm² in side, 12.8 gf/cm² in the back side. Therefore, clothing pressure of brassiere was influenced to the greater extent by body shape and measuring points on human body than by the position of hook-and-eye and body motion.

• Journal of Mechanical Science and Technology
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• 제16권11호
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• pp.1540-1549
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• 2002

Experimental results are presented for the effects of coil diameter, system pressure and mass flux on dryout pattern of two-phase flow in helically coiled tubes. Two tubes with coil diameters of 215 and 485 mm are used in the present study, Inlet system pressures range from 0.3 to 0.7 MPa, mass flux from 300 to 500 kg/㎡s, and heat flux from 36 to 80 kw/㎡. A partial dryout region exists because of the geometrical characteristics of the helically coiled tube. The length of the partial dryout region increases with coil diameter and system pressure. On the other hand, it decreases with increasing mass flux. The critical quality at the tube top side increases with mass flux, but decreases with increasing system pressure. This tendency is more notable when the coil diameter is larger. When the centrifugal force effect becomes stronger, dryout starts at the top and bottom sides of the tube. However, when the gravity effect becomes stronger, dryout is delayed at the tube bottom side. In some cases when the mass flux is low, dryout occurs earlier at the outer side than at the inner side of the tube because of film inversion.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.151-159
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• 2006

A one-dimensional numerical analysis is carried out to investigate the effects of inlet gas humidities, inlet gas pressures, and thicknesses of membrane on the performance of a proton exchange membrane fuel cell. It is found that the relative humidity of inlet gases at anode and cathode sides has a significant effect on the fuel cell performance. Especially, the desirable fuel cell performance occurs at low relative humidity of the cathode side and at high humidity of the anode side. In addition, an increase in the pressure ranging from 1 atm to 4 atm at the cathode side results in a significant improvement in the fuel cell performance due to the convection effect by a pressure gradient toward the anode side, and with decreasing the thickness of membrane, the fuel cell performance is enhanced reasonably.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1705-1709
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• 2005

The hydraulic LSD which uses the principle of gear pump is packed with viscous oil in tight container. When a slip occurs on one wheel, the hydraulic LSD generates torque caused by high oil pressure in the container. In this study, two dimensional(2-D) side pinion gear model was developed for hydraulic LSD. Using that model the flow analysis was conducted to preestimate pressure distributions of the side pinion gear according to the variations in the design factors such as oil viscosity, gear gap and rpm. Then, applying the obtained pressure distributions on the side pinion gear, finite element analysis was conducted to evaluate the torque characteristics. From the analysis results, the torque characteristics according to the design factor variations were evaluated.