• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.237-240
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• 2003

Gas turbines are extensively used in flight propulsion, electrical power generation, and other industrial applications. During its life span, a turbine blade is taken out periodically for repair and maintenance. This includes re-coating the blade surface and re-drilling the cooling holes/channels. A successful laser re-drilling requires the measurement of a hole within the accuracy of ${\pm}0.15mm$ in position and ${\pm}3^{\circ}$ in orientation. Detection of gas turbine blade/vane cooling hole position and orientation thus becomes a very important step for the vane/blade repair process. The industry is in urgent need of an automated system to fulfill the above task. This paper proposes approaches and algorithms to detect the cooling hole position and orientation by using a vision system mounted on a robot arm. The channel orientation is determined based on the alignment of the vision system with the channel axis. The opening position of the channel is the intersection between the channel axis and the surface around the channel opening. Experimental results have indicated that the concept of cooling hole identification is feasible. It has been shown that the reproducible detection of cooling channel position is with +/- 0.15mm accuracy and cooling channel orientation is with +/$-\;3^{\circ}$ with the current test conditions. Average processing time to search and identify channel position and orientation is less than 1 minute.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.269-274
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• 1999

Various method have been developed for mass concrete structures to reduce the temperature increase of concrete mass due to exothermic hydration reactions of concrete compounds and thereby to avoid thermal cracks. One of the methods widely acceptable for practical use is pipe cooling, in which cooling is achieved by circulating cold water through thin-wall steel pipes embedded in the concrete. A numerical simulation was performed to investigate the effectiveness of pipe cooling. A three-dimensional finite element method was proposed to analyse the transient three-dimensional heat transfer between the hardening concrete and the cooling water in pipe and to predict the stress development during the curing process. The effects of the cement type and content and the environment were taken into consideration by the heat generation rate and the boundary conditions, respectively. In order to test the validity of the numerical simulation, a model RC structure with pipe cooling was constructed and the time-dependent temperature and stress distributions within the structure as well as the variation of the temperature of cooling water along the pipe were measured. The results of the simulation agreed well the experimental measurements. The results of this study have important implications for the optimal design of the cooling pipe layout and for the estimation of thermal stress in order to eliminate thermal cracks.

• 한국정밀공학회지
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• 제29권2호
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• pp.185-192
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• 2012

The paper presents the development of a cooling circuit design system that automatically creates 3D cooling circuit on a given section plane conforming to design specifications, generates 3D solid model of cooling line segments defined on a 2D sketch plane, and verifies interference of 3D cooling channel with the molding die surface. The system was developed mainly for designing plastic injection molding die of vehicular lamp, which helps the mold designer to rapidly construct cooling circuits but also reduce designer's unintended mistakes by conforming to the dimensional design specifications. It is used by an injection molding die manufacturing company in Korea, and reported approximately 20% reduction of cooling channel design time.

• 제어로봇시스템학회논문지
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• 제14권1호
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• pp.36-41
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• 2008

Cooling tower is an important equipment of the cooling systems for large buildings like factory and department store. Water used for cooling in cooling tower is reused continuously. If the water is polluted, corrosion and scale can happen at equipments and pipes. In order to prevent this problem, it is necessary to control the water quality using chemicals. To control the water quality, an automatic control system is designed, fabricated, and experimented. The control system is based on an imbedded microcontroller. Relays are used for power driving, an LCD and LED for display, and RS485 for remote data acquisition. Monitoring program is also developed for easy man-machine interface and extraction of data stored in the imbedded processor and EEPROM. The control system calculates amounts of chemicals necessary using sensor data and injects the chemicals into the cooling tower on proper time. The developed water quality control system is expected to reduce cost of maintenance and extend the lifetime of the cooling systems with low cost.

• KSBB Journal
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• 제18권5호
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• pp.418-423
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• 2003

발효조의 냉각수 공급 제어 신호와 냉각수의 유출입 지점의 온도를 온라인으로 측정하여 이 값들로부터 냉각량을 추정할 수 있는 실험식을 얻었다. 회분식 배양을 통하여 냉각량이 온라인으로 측정될 수 있음을 확인하였고 기질의 재투입시 냉각량의 변화를 통하여 유가배양의 제어변수로 활용할 수 있음을 점검하였다. 미리 프로그램된 목표 냉각량의 증가곡선에 따라 냉각량이 증가되면서 세포가 자라도록 유가배양을 실시하였다. 본 연구를 통하여 냉각량의 온라인 측정방법을 제시하였고 이를 유가배양 제어변수로 활용하여 세포의 성장속도를 조절할 수 있음을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.254-257
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• 2008

For crystalline slags, of which the viscosity rapidly increases at $T_{cv}$ due to the formation of crystalline phases, the Tcv is affected by measurement conditions. In this study, we investigated the effect of cooling rate, and alumina dissolution on the determination of $T_{cv}$. Using synthetic slag samples based on the composition of Alaska Usibelli slag, $T_{cv}$ were determined under a constant cooling rate of $2^{\circ}C$/min, and under rapid cooling with holding time to allow the slag to reach thermal and rheological equilibrium. The effect of alumina dissolution was investigated using platinum lined crucibles. The constant cooling resulted in lower $T_{cv}$ by $33^{\circ}C$ as compared to the equilibrium measurements. Under $2^{\circ}C$/min cooling, the blocking alumina dissolution resulted in lower $T_{cv}$ by $23^{\circ}C$. When the $T_{cv}$ was measured under $2^{\circ}C$/min cooling using an alumina crucible, therefore, the effects of a constant cooling is somewhat offset by the alumina dissolution effect, and bring the measured value closer to the true value.

• 설비공학논문집
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• 제26권10호
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• pp.467-473
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• 2014

Since the operating conditions of HVAC systems are different from those for which they are designed, on-going commissioning is required to optimize the energy consumed and the environment in the building. This study presents a methodology to analyze operational data and its applications. A predicted operation model is to be produced through a statistical data analysis using multiple regressions in SPSS. In this model, the dependent variable is the pre-cooling time, and the independent variables include the power output of the supply air inverter during pre-cooling, the supply air set temperature during pre-cooling, the indoor temperature-indoor set temperature just before pre-cooling, supply heat capacity, and the lowest outdoor air temperature during non-cooling/non-heating hours. The correlation coefficient R2 of the multiple regression model between the pre-cooling hour and the internal/external factors is of 0.612, and this could be used to provide information related to energy conservation and operating guidance.

• 한국수소및신에너지학회논문집
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• 제30권3호
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• pp.237-242
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• 2019

In the hydrogen refueling station (HRS), it is need the pre-cooling system (PCS) to limit the inside temperature ($85^{\circ}C$) of the onboard thank (700 bar) and to charge the hydrogen at short time (within 3 minutes) to fuel cell electric vehicle (FCEV). From those safety reasons, the temperature of hydrogen gas must be controled $-33^{\circ}C$ to $-40^{\circ}C$ in PCS. The cooling test of the gaseous ($N_2$, He, $H_2$) was carried out using heat exchanger (pre-cooler) by indirect cooling and direct cooling method. It was confirmed that the temperature of hydrogen gas had below $-40^{\circ}C$ at below $-75^{\circ}C$ of chiller temperature in direct cooling.

• Tribology and Lubricants
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• 제39권2호
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• pp.76-80
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• 2023

This paper describes an experimental investigation of the effect of cooling flow rate on gas foil thrust bearing (GFTB) performance. In a newly developed GFTB test rig, a non-contact type pneumatic cylinder provides static loads to the test GFTB and a high-speed motor rotates a thrust runner up to the maximum speed of 80 krpm. Force sensor, torque arm connected to another force sensor, and thermocouples measures the applied static load, drag torque, and bearing temperature, respectively, for cooling flow rates of 0, 25, and 50 LPM at static loads of 50, 100, and 150 N. The test GFTB with the outer radius of 31.5 mm has six top foils supported on bump foil structures. During the series of tests, the transient responses of the bearing drag torque and bearing temperature are recorded until the bearing temperature converges with time for each cooling flow rate and static load. The test data show that the converged temperature decreases with increasing cooling flow rate and increases with increasing static load. The drag torque and friction coefficient decrease with increasing cooling flow rate, which may be attributed to the decrease in viscosity and lubricant (air) temperature. These test results suggest that an increase in cooling flow rate improves GFTB performance.

• 한국산학기술학회논문지
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• 제13권2호
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• pp.485-491
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• 2012

최근 국내 섬유산업의 생산량이 증가함에 따라 섬유산업에서 에너지 소비는 계속 증가되고 있는 실정이다. 기존의 염색기는 고온 고압의 특성을 가지고 있기 때문에 염색 후 냉각을 하기 위하여 열교환기를 통한 간접냉각방식을 채택하고 있다. 이러한 간접냉각방식은 물의 소모량이 많으며 작업 시간 또한 오래 걸리는 문제점이 있고 냉각시 염액의 고착으로 인해 냉각 후 환원세정 및 수세를 수차례 하므로 에너지가 많이 소비된다. 따라서 본 논문에서는 고온 고압 액류 염색기의 열교환기에 의한 간접냉각방식을 염색기내에 냉수를 직접 공급하는 직접냉각방식으로 대체하기 위한 장치를 개발하여 기존의 염색기에 적용하여 냉각과 동시에 환원세정공정을 생략하고 수세공정을 단축시키면서 전공정을 마무리함으로써 전체 작업공정을 줄이고 에너지 소비를 절감하는 등의 생산성을 획기적으로 향상시킬 수 있는 직접냉각수세장치를 제안하며, 시제작품을 제작하고, 실제 염색기에 적용하여 기존의 간접 냉각 방식의 염색기와 성능, 자원 및 에너지 절감율을 비교하였다. 또한 시제작품을 적용한 염색기의 염색성 실험을 하였다.