• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.767-772
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• 2006

The SWTR(Surface Water Treatment Rule) requires achieving removal 99.9% Giardia and 99.99% Virus. To remove Giardia and Virus, disinfection process is essential process. CT is important index for Disinfection performance. CT value is expressed by CXT. C is represented by disinfection concentration and T is represented by $T_{10}$ which means 90% contact time in clearwell. To improve Disinfection performance, it is desirable to increase $T_{10}$. Primary factor affected $T_{10}$ is flow Pattern. Because guide wall change that flow pattern is uniform, we have installed guide wall to increase $T_{10}$. In this paper, we have performed numerical analysis for clearwell installed symmetric guide wall and center divided guide wall using CFD. We have analyzed flow pattern and $T_{10}$ in each clearwell. And. we compare symmetric guide wall with center divided guide wall in flow pattern and $T_{10}$.

• 상하수도학회지
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• 제21권6호
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• pp.755-761
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• 2007

Disinfection performance in clearwell is generally measured by CT, which is expressed by $C{\times}T$. C is represented by disinfection concentration, and T is represented by $T_{10}$ which means 90% contact time in clearwell. In order to improve Disinfection performance, augmentation of $T_{10}$ is required. Guide wall has been generally used to improve $T_{10}$ because $T_{10}$ changes according to flow field. In this study, porous media is proposed instead of guide wall, and disinfection performance between guide wall and porous media wall are compared. Flow field and $T_{10}$ in each clearwell are investigated as well. Improved Disinfection performance appear in case of porous media wall compare to guide wall, and best performance occur in porosity factor ${\beta}$ 1e+4.

• 한국안전학회지
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• 제38권2호
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• pp.44-51
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• 2023

With the recent increase in gas energy use, risk management for explosion accidents has been emphasized. Protective walls can be used to reduce damage from explosions. The KOSHA GUIDE D-65-2018 suggests the minimum thickness and height of protective walls, minimum reinforcement diameter, and maximum spacing of reinforcements for the structural safety of the protective walls. However, no related evidence has been presented. In this study, the blast load carrying capacity of the protective wall was analyzed by the pressure-impulse diagrams while changing the yield strength of the reinforcement, concrete compressive strength, reinforcement ratio, protective wall height, and thickness, to check the adequacy of the KOSHA GUIDE. Results show that failure may occur even with design based on the criteria presented by KOSHA GUIDE. In order to achieve structural safety of protective walls, additional criteria for minimum reinforcement yield strength and maximum height of protective wall are suggested for inclusion in KOSHA GUIDE. Moreover, the existing value for minimum reinforcement ratio and the thickness of the protective wall should be increased.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.257-258
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• 2012

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 2부
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• pp.97-98
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• 2011

The number of high-rise buildings has increased year after year, with there currently being 5 projects in progress to construct buildings higher than 100 stories in Seoul alone. The construction cost for such high-rise buildings is significantly higher than the cost for a conventional low-rise building, while maintenance costs are expected to be two to three times higher. To reduce the maintenance cost of a high-rise building, there is the need for a guide rail to be used for maintenance, which is why there is the need for research on the guide rail system. For this reason, as preliminary research to develop a guide rail, this study aims to derive the factors increasing construction cost by taking the installation of a guide rail into account. This is expected to lay the groundwork for the design and construction of guide rails for high-rise building maintenance.

• Coupled systems mechanics
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• 제7권4호
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• pp.421-440
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• 2018

In this study, a computational method for wall shear stress combined with an implicit direct-forcing immersed boundary method is presented. Near the immersed boundaries, the sub-grid stress is determined by a wall model in which the wall shear stress is directly calculated from the Lagrangian force on the immersed boundary. A coupling mathematical model of the transition process for a model Francis turbine comprising turbulent flow and rotating rigid guide vanes is established. The spatiotemporal distributions of pressure, velocity, vorticity and turbulent quantity are gained with the transient process; the drag and lift coefficients as well as other forces (moments) are also obtained as functions of the attack angle. At the same time, analysis is conducted of the characteristics of pressure pulsation, velocity stripes and vortex structure at some key parts of flowing passage. The coupling relations among the turbulent flow, the dynamical force (moment) response of blade and the rotating of guide vane are also obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.80-84
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• 1996

The effects of guide pads on burnishing action and accuracy of machined hole are investigated in drilling with burnishing drill using a speciaaly designed tool experimentally. The cutting forces are balanced at the small forward regions of guide pads. The burnishing action takes place under a high contact pressure between the bore wall and those regions. The over size mechanism of machined hole by the guide pads is discussed.

• 한국건축시공학회지
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• 제12권2호
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• pp.220-229
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• 2012

매년 초고층 건축물 관련 프로젝트가 증가하고 있으며, 초고층 건축물의 높이가 증가함에 따라 시공법과 함께 유지관리 방법도 기존방식과는 큰 차이를 보이고 있다. 또한 유지관리 업무 중 가장 빈번하게 수행되는 외벽 청소작업을 보다 안전하게 작업하기 위한 근본적인 대책으로 청소작업의 자동화 및 기계화가 요구되고 있다. 그리고 초고층에서 발생되는 돌풍 등 외부환경의 영향에 대응할 수 있는 방법으로 가이드레일 청소로봇 시스템이 제기되고 있다. 따라서 본 연구는 초고층 건축물 외벽 청소작업의 자동화 및 기계화를 위한 선행연구로써, 외벽 청소로봇 운용을 위한 가이드레일 기본단위유닛 도출과 가이드레일 개념(안)을 개발하는 것이다. 이를 통하여 초고층 건축물 외벽 청소로봇운용을 위한 선행연구이며, 운용에 필요한 최적의 가이드레일 최종설계의 기반을 마련하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1279-1280
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• 2013

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.69-77
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• 1999

The stabbing guide is often used to guide an add-on pile into an existing pile in offshore jacket installation. It provides a pile alignment for a welding tie-in in static condition as well. Even stabbing guide is an essential component in pile installation, it is not considered as a permanent offshore structure. In this regard, there is not a define design guideline proposed. In API RP 2A WSD, it briefly define the design considerations of stabbing guide. The failure of stabbing guide can cause a greate economical loss and a serious impact to the project schedule. Stabbing guide design should consider many factors considering actual work conditions for both static and dynamic situations. In the paper, a design method is proposed by appling the plate theory and it is confirmed numerically with FEM modeling. The geometry of stabbing guide is assumed as a cylinder shape with various wall thickness and effective length. The various thickness, effective length and pile size are compared for stable stabbing guide design.