• 한국산학기술학회논문지
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• 제10권1호
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• pp.6-11
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• 2009

본 논문에서는, 청정지역내에서 다수의 유리 기판을 적재하여 반송하는 롤러 컨베이어 시스템에서, 롤러와 카세트 사이의 기계적 마찰로 인해 발생하는 오염입자에 의한 유리 기판의 오염여부를 판단하기 위해, 시스템 내부의 유동장을 전산유체역학 기법을 통해 해석하였다. 수치해석 결과 일정 속도로 이동하는 카세트 하부에 큰 와류가 생성되는 것을 확인하였다. 그러나 이 와류는 후면에서 유입되는 강한 기류와, 상부 FFU에서 공급되어 하부로 배기되는 기류로 인해, 카세트의 하부 영역에만 갇히게 되는 것으로 나타났다. 따라서 카세트와 롤러 사이의 기계적 마찰로 인해 오염입자가 발생하여도 상부로 이동할 수 없어 유리 기판의 오염 가능성은 낮았다. 또한 이동속도가 빨라짐에 따라 유리 평판 사이의 공기 유동의 방향이 평판의 점성 전단력에 의해 역방향으로 바뀌게 됨을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.674-679
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• 2000

An air handling unit(AHU) has been usually designed by manual calculations. Drawing works together with design calculations should be redone far every designing work, and also be needed to make some corrections of them. In order to design the AHU more efficiently, an AHU program has been developed. The developed program on the Windows environment is operated by the graphic user interface(GUI) realized using the Visual Basic Interpreter. The program provides calculation sheet of coils, weights and pressures in a MS-Excel file format as well as design drawing of the AHU in a Auto CAD file format idealized by AutoLISP. Those files of the commercial softwares make easier for a designer to transfer design results to the another company for bid via e-mail.

• 한국산업보건학회지
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• 제15권3호
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• pp.166-175
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• 2005

Health effects associated with metal working fluid (MWF) exposures include dermatitis, respiratory disease, hypersensitive pneumonitis, and asthma. Frequently, occupational exposures to MWFs are controlled by ventilating an enclosure with an air cleaning unit that includes a fan preceded by various kinds of filtration. There are several kinds of air cleaning units used in machining centers. But the associated troubles have hindered from efficiently using these devices. The main problem is the relatively short period of filter replacement. The reason is that the air cleaning units usually do not have the de-oiling systems, thus leading the earlier clogging of filters and reducing the flow rate of hood. Thus, the first stage of study was conducted to overcome this problem by developing the new oil mist collector equipped with the easy de-oiling system. The principle of de-oiling is that the centrifugal force generated by spinning the drum covered by filter fabric separates oils from the filter fabric. It would be very similar to the spin-dry laundry. By adopting this de-oiling technique, the problems associated with the conventional oil mist collectors could be solved. Several tests/analyses were performed to make the lab-scale oil mist collector. The collection efficiencies and the de-oiling efficiencies of commercially available filter fabrics were tested. Subsequently, the endurance test were conducted by observing SEM photos of filter fabrics and measuring tensile strength/expansion coefficient after spinning the filter drum for 20 minutes at the different rotation speeds. By doing these experiments, the most appropriate filter fabric and rotation speed/duration were selected. Finally, the new oil mist collector was designed. In the near future, this device must be tested in the real machining center.

• 설비공학논문집
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• 제16권10호
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• pp.914-922
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• 2004

In this study, measurement and analysis of energy consumption of a research building have been conducted. The energy audit procedure includes monitoring of electricity and LNG consumption over a period of three yews from 2000 to 2002. Data acquisition system for collecting energy consumption data of HVAC equipment such as chillers, fan filter units, AHUs, cooling towers, boilers, pumps, fan coil units, air compressors and etc. has been installed in a building located in Seoul. Data collected at an interval of 1 minute are analyzed for studying the energy consumption pattern of a research building. Percentage of energy consumption of all HVAC equipment is $51.0\%$ in 2000, $55.4\%$ in 2001, and $62.3\%$ in 2002, respectively. Electricity consumption of chillers accounts for $17.6\%$ of the total energy consumption, which is the largest. Annual energy consumption-rate per unit area is $840.5Mcal/m^2{\cdot}y$ in 2000, $1,064.8Mcal/m^2{\cdot}y$ in 2001, and $1,393.0Mcal/m^2{\cdot}y$ year 2002, respectively.

• 설비공학논문집
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• 제22권4호
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• pp.225-233
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• 2010

We performed 3 dimensional numerical study on the improvement of the airflow deflection in the cleanroom of Class 1000, which is presently operated for the manufacturing process in Korea. The Deflection angle and the non-uniformity were investigated to analyze the airflow characteristics and the performance of cleanroom with variations of the cleanroom occupancy state, the filters' arrangement, and the floor return air system. From the numerical results, we found out that the airflow pattern of the cleanroom is more unidirectional and stable in the condition of at-rest than in the condition of as~built. It is due to that the equipments installed in the cleanroom play a role like partitions, which prevent the airflow from inclining toward the recirculation air duct. And it is needed to arrange the filter units parallel to the equipments array without a gap between them for maintaining the unidirectional airflow pattern. Finally, we knew that it is very important to install the partition like the eyelid above the equipment to keep the unidirectional airflow around the equipments and remove the contaminants quickly.

• 보존과학회지
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• 제36권1호
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• pp.28-36
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• 2020

The storage environment of a Japanese woodblock print collection was assessed for organic acids. The active air sampling method was used to collect organic acid emissions in the low microgram range from areas of a selected woodblock print with different pigments, following which an off-gassing mitigation strategy based on the fan filter unit(FFU) system was investigated. Research findings revealed that the off-gassing behavior of woodblock prints is significantly impacted by storage practices and to a lesser degree by the pigments. The FFU system can be used as a mitigation strategy, but the permanence of the results depends on the storage conditions.

• 대한기계학회논문집B
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• 제28권5호
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• pp.560-568
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• 2004

We performed the numerical study on the characteristics of the 3-D airflow and dynamic cross contamination in the photolithography process cleanroom. The nonunifurmity, the deflection angle and the global cross contamination were used for analyzing the characteristics and performances of cleanroom. From the numerical results, we knew that the airflow characteristics of the cleanrooms are largely affected by the porosity of panel and the adjustment of dampers and the global cross contamination varies with the location of source and the passage of time through the concentration ratio.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.151-156
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• 2003

We performed the numerical study on the characteristics of the airflow and cross contamination in the photolithography process cleanroom. The nonuniformity, the deflection angle and the global cross contamination were used for analyzing the characteristics and performances of cleanroom. We knew that the airflow characteristics of the cleanrooms are largely affected by the porosity of panel and the adjustment of dampers. And the numerical result showed that the global cross contamination varies with the location of source and the passage of time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.231-235
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• 2005

Recently, some semiconductor and LCD manufacturers require equipment suppliers to serve the data of composite noise for clean room. In this study, we evaluate the composite noise of clean room by numerically and experimentally. The value of experimental result is more higher than calculated one as much as 1$\sim$2dB(A).

• 한국입자에어로졸학회지
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• 제14권4호
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• pp.181-189
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• 2018

In this study, the risk rates of different contamination sources of the contaminant in a minienvironment were analyzed through Computational Fluid Dynamics (CFD) simulation. The airflow pattern characteristics can only predict the qualitative variation of contaminant concentration, but cannot evaluate the quantitative variations in the risk rate of sources. From the results, the ambient contamination sources mainly affect wafers in the Front Opening Unified Pod (FOUP), whereas the internal contamination sources mainly affect wafers laid on the robot arm in the minienvironment. And the purging plenum system is very useful in protecting the wafers in the FOUP from contaminants transferred from the Fan Filter Unit (FFU). However, this system is unable to protect the wafers on the robot arm from internal contaminants and the wafers in the FOUP from sources of the interface between the FOUP and the minienvironment.