• 한국기계가공학회지
• /
• 제17권5호
• /
• pp.84-90
• /
• 2018

When producing a plastic horn cover for an automobile, since the interval between the ribs on the inner surface is narrow, conventional cooling channels cannot be applied and cooling of the mold is difficult. For this reason, the molding operation cannot be completed within a set cycle time. In this study, a conformal cooling channel was applied on the mold to solve the cooling problem. Injection molding simulation was carried out to confirm the effectiveness of the conformal cooling channel. In the analysis results, the mold temperature at the rib section decreased by 33%, and the mold temperature also decreased by 31%. This reduction in temperature allowed for molding within a set cycle time and demonstrated the effectiveness of the conformal cooling channel.

• 한국생산제조학회지
• /
• 제18권4호
• /
• pp.417-422
• /
• 2009

The injection mold cooling circuit optimization was studied with a response surface method in the previous research. It took so much time to find an optimum solution for a large product due to an extensive amount of calculation time for the CAE analysis. In order to use the optimization technique in the actual design process, the calculation time should be much reduced. In this study, we tried to reduce the number of design variables with the concept of the close relationship between the depth and the distance of cooling channel. The optimum ratio of the distance to the depth of cooling channels for a 2-dimensional problem was 2.0 so that the optimum ratio was again sought out for 4 large automotive parts. Therefore, the number of design variables for the cooling circuit optimization can be reduced in half, resulting in much faster running time for the optimization as a design tool.

• 한국추진공학회지
• /
• 제7권2호
• /
• pp.54-61
• /
• 2003

본 연구에서는 액체로켓에서 널리 사용되는 재생냉각시스템이 장치된 실험용 액체로켓 엔진을 설계하고 제작하여 연소실험을 수행한 내용을 다루었다. 설계 프로그램을 이용하여 엔진을 설계하였고 이를 바탕으로 엔진을 제작하였다. 연소실험을 통해 측정한 열유속이 계산에 의한 해석결과와 유사하므로 실제로켓엔진의 설계 및 제작에 설계 프로그램을 이용할 수 있음을 확인하였다. 또한 연소시 생성된 탄소층이 냉각성능에 미치는 영향을 간단히 고찰하였다.

• 한국자동차공학회논문집
• /
• 제22권2호
• /
• pp.1-6
• /
• 2014

In-wheel driving inverter inside engine room sometimes operates in the harsh environment like high temperature of about $105^{\circ}C$. Especially, the size and power density of the inverter has become smaller and more increased. Thus, it is essential to manage the temperature of the inverter with IGBT (Insulated Gate Bipolar Transistor) switching devices for performance and endurance, because the temperature can be getting increase. In this paper, we performed the thermal flow analysis of inverter models with wave type and pin fin type cooling channels, and investigated the heat transfer characteristics of the inverter models using cooling water on channels at 8 L/min and $65^{\circ}C$. Also, we compared the thermal performance under various conditions such as coolant flow rate and layered power module structure. Therefore, we determined the feasibility of the initial inverter models and the thermal performance enhancement.

• 항공우주기술
• /
• 제7권1호
• /
• pp.129-135
• /
• 2008

30톤급 액체로켓엔진용으로 개발된 일체형 재생냉각 연소기는 연료를 확대노즐부의 중간에서 공급하는 방식으로 설계되었으며, 노즐 끝단에서 공급되는 방식에 비해 냉각유로는 복잡해지지만 열유속이 상대적으로 낮은 확대노즐부의 냉각유량을 줄임으로서 압력손실을 감소시키는 동시에 공급라인을 포함한 연소기 전체 외경이 줄어들어 엔진 구성에 유리한 장점을 있다. 본 연구에서는 이와 관련한 연료링과 양 방향 냉각 채널, 그리고 연결/분기 유로에 대해 수치해석을 통한 세밀한 설계검토를 수행하였다.

• 한국추진공학회지
• /
• 제20권4호
• /
• pp.94-103
• /
• 2016

액체로켓엔진에서의 재생냉각 채널은 높은 온도의 연소가스로부터 연소실 내벽을 효율적으로 냉각하기 위해 사용되며, 냉각채널 설계를 위해서는 열전달 특성과 압력손실 특성을 미리 예측하여야 한다. 본 연구에서는 서로 다른 형상을 갖는 5개의 냉각채널을 설계하고, 커터와 엔드밀로 채널을 제작하였다. 채널을 흐르는 유속과 후단 압력조건을 달리하여 가공방법, 채널 형상, 유동조건에 따른 압력손실을 실험적으로 측정하여 해석결과와 비교를 수행하였다. 동일 형상 및 유동조건에서 커터로 가공된 채널이 엔드밀로 가공된 채널보다 압력손실이 적었다. 또한 채널 형상, 유동조건에 따라 실험결과와 해석결과의 압력손실 비가 달라짐을 확인할 수 있었다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2064-2069
• /
• 2008

The Resonance Control Cooling System (RCCS) prototype installed in KAERI site has been designed to control the resonant frequency of the normal conducting drift tube linac (DTL) for the Proton Engineering Frontier Project (PEFP). The RCCS water pumping skid is composed of two channels as a by-passing the cooling water and a plate heat exchanger. The required temperature can be achieved by mixing both channels in order to control its the resonant frequency at 350 MHz. The temperature controlled water pumping skid operates in combination with the Low Level Radio Frequency (LLRF) system. We have discussed the design, modeling with each components, control scheme, fabrication and test results of the water pumping skid for resonant frequency control of the DTL cavity. In conclusion, the fabricated RCCS prototype through the optimization of modeling has corresponded with the design requirement and concept.

• 설비공학논문집
• /
• 제21권3호
• /
• pp.149-156
• /
• 2009

A small-scale thermoelectric cooling system was built in an effort to enhance the performance of the refrigeration system by utilizing the water-cooled jacket which was attached to the hot side of the thermoelectric module. Considered design parameters for the water-cooled jacket were the geometry of the flow passage inside the jacket and the flow rate of cooling water. The higher flow rate of cooling water in the jacket resulted in a better performance of the refrigeration system. The increase in the number of channels for water flow passage inside the cooling jacket also showed significant improvement on the performance of the thermoelectric cooling system such as the cooling capacity and the COP of the refrigeration system.

• 대한기계학회논문집A
• /
• 제35권12호
• /
• pp.1635-1640
• /
• 2011

본 논문의 목적은 수치해석을 통한 자동차 와이퍼 소켓 부품 제작용 오버몰딩 금형의 냉각 시스템 설계이다. 초기 금형설계에 대한 수치해석을 수행하여 제품내 높은 온도 분포를 나타내는 열집중 영역을 도출하였다. 열집중 영역의 냉각특성 개선을 위하여 직선형 냉각수로와 체적 열 흡수부의 2 가지 냉각시스템을 고려하였다. 직선형 냉각수로의 설계를 도출하기 위하여 냉각수로의 직경과 위치가 냉각 특성과 제품 품질에 미치는 영향을 정량적으로 분석하였다. 또한 체적 열 흡수부 설계가 제품 냉각 특성과 변형에 미치는 영향을 고찰하였다. 최종적으로 체적 열 흡수부가 추가된 다중 슬라이스 오버몰딩 금형이 냉각 특성과 제품품질을 동시에 향상시킬 수 있음을 알 수 있었다.

• Nuclear Engineering and Technology
• /
• 제45권2호
• /
• pp.257-264
• /
• 2013

In Canada Deuterium Uranium (CANDU)-type nuclear power plants, the reactor is composed of 380 fuel channels and refueling is performed on one or two channels per day. At the time of refueling, the fluid force of the cooling water inside the channel is exploited. New fuel added upstream of the fuel channel is moved downstream by the fluid force of the cooling water, and the used fuel is pushed out. Through this process, refueling is completed. Among the 380 fuel channels, outer rows 1 and 2 (called the FARE channel) make the process of using only the internal fluid force impossible because of the low flow rate of the channel cooling water. Therefore, a Flow Assist Ram Extension (FARE) tool, a refueling aid, is used to refuel these channels in order to compensate for the insufficient fluid force. The FARE tool causes flow resistance, thus allowing the fuel to be moved down with the flow of cooling water. Although the existing FARE tool can perform refueling in Korean plants, the coolant flow rate is reduced to below 80% of the normal flow for some time during refueling. A Flow rate below 80% of the normal flow cause low flow rate alarm signal in the plant operation. A flow rate below 80% of the normal flow may cause difficulties in the plant operation because of the increase in the coolant temperature of the channel. A new and improved FARE tool is needed to address the limitations of the existing FARE tool. In this study, we identified the cause of the low flow phenomena of the existing FARE tool. A new and improved FARE tool has been designed and manufactured. The improved FARE tool has been tested many times using laboratory test apparatus and was redesigned until satisfactory results were obtained. In order to confirm the performance of the improved FARE tool in a real plant, the final design FARE tool was tested at Wolsong Nuclear Power Plant Unit 2. The test was carried out successfully and the low flow rate alarm signal was eliminated during refueling. Several additional improved FARE tools have been manufactured. These improved FARE tools are currently being used for Korean CANDU plant refueling.