• 전기학회논문지
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• 제63권3호
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• pp.431-436
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• 2014

In this paper, temperature change properties on the 210kW-class Interior Permanent Magnet Synchronous Motor (IPMSM) are performed with the cooling performance of a water cooling device through the thermal characteristic analysis of the IPMSM considering a real driving pattern of urban railway vehicles. First, the thermal analysis modeling of 210kW-class IPMSM, which is an alternative to the conventional induction motor, and its water cooling device is conducted. Next, the thermal characteristic analysis of the IPMSM considering a real driving pattern of urban railway vehicles is performed using 2-Dimensional FEM tool. Finally, the calculated characteristic results are analyzed. Consequently, it is confirmed that the internal temperature of the 210kW-class IPMSM may be lowered to about 42~52% by maintaining the coolant flow rate of the water cooling device (Cross sectional shape of the pipe has 220mm width and 10mm height) for 0.2kg/s level.

• 한국유체기계학회 논문집
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• 제19권5호
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• pp.42-49
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• 2016

Aerodynamic analysis of a low-voltage electric motor has been performed with various inlet vent shapes. Effects of inlet vent shape on aerodynamic performance of a motor cooling fan have been investigated numerically using three-dimensional Reynolds-averaged Navier-Stokes equations. The k-${\varepsilon}$ turbulence model was used for the analysis of turbulence. The finite volume method and unstructured tetrahedral grids were used in the numerical analysis. Optimal grid system in the computational domain was selected through a grid-dependency test. From the results of the flow analysis, considerable energy loss by flow separation was observed in the flow passage. It was found that mass flow rate through the cooling fan in the low-voltage motor can be increased by modifying the inlet vent shape. And, some inlet vent shapes were suggested to improve the aerodynamic performance of the motor cooling fan.

• 한국유체기계학회 논문집
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• 제15권5호
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• pp.27-31
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• 2012

Turbine inlet temperature is steadily increasing to achieve high specific thrust and efficiency of gas turbine engines. Turbine cooling technology is essential to increase turbine inlet temperature. For this study, a small or medium sized aircraft engine of 10,000 lbf class with the turbine inlet temperature of $1,400^{\circ}C$, the engine overall pressure ratio of 32.2, and the bypass ratio of 5 was set as the baseline model and its performance analysis was performed at the design point. The engine has the performance of 10,013 lbf thrust and the specific fuel consumption of 0.362 lbm/hr/lbf. The thrust and the specific fuel consumption of the baseline model were compared with those of similar class engines. Based on these results, the turbine design requirements were assigned. In addition, the parametric analysis of the engine, related to aerodynamic and cooling design of the high pressure turbine, was performed. Based on the baseline model engine, the influence of turbine inlet temperature, cooling flow ratio, and high pressure turbine efficiency variations on the engine performance was analyzed.

• 한국추진공학회지
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• 제10권2호
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• pp.53-61
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• 2006

3차원 냉각 채널을 가지는 재생 냉각 시스템에 대하여 축대칭 열유속 모델을 이용한 축대칭 열해석을 수행하고자 하였다. 연소실 벽면에서의 급격한 온도 분포 및 열전달량을 정확히 모사하기 위한 격자 테스트 수행하고, 냉각재와 연소 가스의 온도에 따른 물성치 변화가 냉각 성능 예측에 미치는 영향들을 살펴보았다. 핀효율을 이용한 축대칭 열유속 모델이 3차원 냉각 채널에서의 열전달량과 동일한 열전달량을 나타낼 수 있도록 정의하였다. 제안된 모델을 이용한 축대칭 해석 결과가 1차원 해석 모델보다 우수하며 3차원 해석 결과에 근접한 온도 분포를 보임을 확인하였다.

• 대한기계학회논문집A
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• 제34권7호
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• pp.935-941
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• 2010

하나로는 한국에 설치되어 있는 열출력 30MW의 개방 수조형 연구로 이다. 이는 발전로와 달리 원자로에서 발생하는 열을 이용하여 전기를 생산하는 것 대신에 원자로의 노심 온도를 유지하기 위하여 냉각탑을 통해 대기로 이 열을 냉각한다. 냉각탑 월간 점검 중에 냉각탑 4번의 냉각팬 감속기가 기준을 상회하는 고진동을 기록하였다. 본 연구의 목적은 고진동의 원인을 찾아 정상적으로 수리하기 위함이다. 연구 방법은 FFT 스펙트럼 기법을 적용하여 고진동의 원인을 분석하였다. 그 결과 고진동 주파수는 피니언 기어의 고유 진동수의 두 배인 354Hz이었다. 피니언 기어를 점검한 결과 이빨 표면이 깨져 있었다. 깨진 피니언 기어를 제거하고 새것으로 교체한 후에는 감속기는 정상적으로 작동하였다.

• 대한기계학회논문집
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• 제12권5호
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• pp.952-958
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• 1988

본 연구에서는 폭방향 불균일 냉각에 따른 열응력이 판변형 및 잔류응력의 주 요원인이라는 고려하에 냉각중에 압연판의 온도분포 및 열응력을 예측할 수 있는 수치 해석 모델을 구성하였다. 온도와 응력 계산에 상변태 현상을 고려하였으며, 판변형 은 압축성분 열응력에 의한 좌굴현상으로 고려하여 해석하였다.

• 한국항공운항학회지
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• 제14권1호
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• pp.15-21
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• 2006

Parametric cycle analysis of a dual-spool, mixed exhaust turbofan engine with turbine blade cooling were described to investigate the effect of turbine blade cooling on the engine performance such as specific thrust and thrust specific fuel consumption. Coolant of low pressure turbine triggers high engine performance loss and cooling effect loss in high pressure turbine. Therefore low pressure turbine coolant should be much more considered for effective design.

• 대한기계학회논문집
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• 제18권4호
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• pp.946-957
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• 1994

In the steel industries, direct rolling process for production of strip from molten metal has been investigated to simplify processes, to minimize energy consumption, and to improve quality of the strip. In this study, two kinds of practicable scale cooling rollers are proposed. And heat transfer analysis of pool region and cooling roller considering flow of molten metal and roll rotation respectively using the finite element method are performed to obtain the proper initial condition and to observe cooling characteristics of cooling roller. From the results, variations of solidification final points and temperature distribution in roller are observed quantitatively according to roll rotation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.451-454
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• 2003

The Oil Coolers is very important unit for the stable thermal performance in machine tools, semiconductor equipments and high precision measuring systems. To select a proper oil cooler for the temperature control of core unit in a machine, not only cooling ability but also static and dynamic sensitivity of temperature sensors are considered. In this paper, the relationship between cooling ability and inflow oil temperature is identified. The cooling ability is increased with the increase of inflow oil temperature. The oil temperature control errors of a cooler are influenced by mainly sensitivity of temperature sensors and heating velocity in a machine. The validity of error cause analysis for temperature control is proved by real cooling experiments with inflow and outflow temperature sensors.

• 한국압력기기공학회 논문집
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• 제8권2호
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• pp.33-41
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• 2012

The component cooling water heat exchangers are critical components in a nuclear power plant. As the operation years of the heat exchanger go by, the maintenance costs required for continuous operation also increase. Most heat exchangers have carbon steel shells, tube support plates and flow baffles. The titanium tube is susceptible to flow induced vibration. The damage on carbon steel tube support rod and titanium tube around cooling water entrance area is inevitable. Therefore, analysis of internal flow around the component cooling water entrance and tube channel is a good opportunity to seek for failure prevention practice and maintenance method. The numerical study was carried out by FLUENT code to find out the causes of tube failure and its location.