• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.95-98
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• 2002

Three-dimensional flow analyses for two different ratios of radius to height of sedimentation bed are implemented to evaluate the effect of blockage ratio of center feed wall and angle of distributor on sedimentation efficiency, and to find the optimal value of those parameters. Sedimentation efficiencies for three different shapes are compared with and without rotation speed. And then, five different combinations of blockage ratio of center feed wall and angle of distributor are compared It reveals that the effect of blockage ratio of center fled wall and angle of distributor is considerable to sedimentation efficiency while rotation effect can be neglected and $0.55 and 33^{\circ}$for blockage ratio of center food wall and angle of distributor, respectively, ive the best sedimentation efficiency.

• 한국유체기계학회 논문집
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• 제7권6호
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• pp.55-61
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• 2004

A numerical procedure for optimizing the shape of three-dimensional sedimentation tank is presented to maximize its sedimentation efficiency. The response surface based optimization is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis for multi-phase flow. Standard $k-{\epsilon}$ model is used as a turbulence closure. Three design variables such as, tank height to center feed wall diameter ratio, blockage ratio of center feed wall and angle of distributor are chosen as design variables. Sedimentation efficiency is defined as an objective function. Full-factorial method is used to determine the training points as a means of design of experiment. Sensitivity of each design variable on the objective function has been evaluated. And, optimal values of the design variables have been obtained.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.425-432
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• 2002

Both numerical and experimental studies on sedimentation efficiency of a sedimentation bed were carried out. Three different structures of sedimentation bed and five different combinations of blockage ratio of center feed wall and angle of distributor are implemented to find the optimal values of geometric parameters. The effect of rotation of the distributor on sedimentation efficiency is also investigated. It reveals that the effect of blockage ratio and angle of distributor on sedimentation efficiency is considerable, while rotation effect can be neglected, and that calculated efficiencies show good agreements with those of experiment, qualitatively.

• 한국유체기계학회 논문집
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• 제6권2호
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• pp.54-61
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• 2003

Both numerical and experimental studies on the sedimentation efficiency of a sedimentation bed were carried out. Three different structures of sedimentation bed and five different combinations of blockage ratio of center feed wall and angle of distributor are implemented to find the optimal values of geometric parameters. The effect of rotation of the distributor on sedimentation efficiency is also investigated. It reveals that the effects of blockage ratio and angle of distributor on sedimentation efficiency are considerable, while rotation effect can be neglected, and that calculated efficiencies show good agreements with those of experiment, qualitatively.

• Journal of electromagnetic engineering and science
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• 제4권4호
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• pp.150-155
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• 2004

Universal design equations are presented for the H-plane T-junction power divider with a circular conducting post in a rectangular waveguide. For a given operating frequency and power split ratio, the post offset from the T-junction center line, the distance between the post and the waveguide wall, and the post diameter can be adjusted to obtain a minimum reflection at the input waveguide. Optimum values of the post offset are given in terms of the normalized frequency and the power split ratio. Corresponding values of the post diameter and the distance of the post from the waveguide wall are given in terms of the normalized frequency and the post offset.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.438-443
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• 2005

Handy paint rollers with simple or no patterns are generally used to transcribe its design to a wall just after painting. However, the types of the patterns are limited to several conventional ones, so that interior planners' or decorators' demands are gradually tending to getting attractive roller designs. In order to obtain abundant kinds of the roller designs, a new advanced 3D machining method should be established for cylindrical models. In this paper, a post-processor that can generate suitable NC data is proposed for multi-axis NC machine tools with a rotary unit. The 3D machining system with the post-processor is also presented for an attractive interior decorating. The machining system allows us to easily transcribe the relief designs from on a flat model to on a cylindrical model. The effectiveness of the proposed 3D machining system using the post-processor is demonstrated through some machining experiments.

• 한국기계가공학회지
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• 제1권1호
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• pp.5-14
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• 2002

Hemisphere shapes were machined for different tool paths and machining conditions with ball endmill cutters. It was also found out how feedrate affect the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Tool deflection, cutting forces and shape accuracy were measured according to the inclination position of the sculptured surface. As the decreasing of inclination position angle, the tool deflection was increased due to the decreased cutting speed when the cutting edge is approaching toward the center. Tool deflection when upward cutting IS obtained less than that of downward cutting and down-milling in upward cutting showed the least tool deflection for the sculptured surface. For down-milling, the cutting resistance of the side wall direction is larger than that of feed direction. It was found that the tool deflection is getting better as tool path is going to far from the center for convex surface.

• 유기물자원화
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• 제28권4호
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• pp.69-75
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• 2020

본 연구에서는 원형침전지의 고액분리 효율을 향상시키기 위해 응집제 없이 lab scale 침강장치에 교반속도(rpm)와 baffle 각도를 조절하여 생응집(bio-flocculation) 실험을 수행하였다. 피드 웰(feed wall)부분을 개량하여 baffle를 설치하고 각도(10°)를 고정한 후 각각의 교반속도(0.0rpm, 0.6rpm, 1.2rpm) 변화에 따른 실험 결과 교반속도 0.6ppm에서, 농축효율이 2.0%, 유출수(SS 농도) 제거효율은 7.8% 상승되는 것으로 분석되어 교반속도에 따른 슬러지의 생응집 효율 향상을 확인할 수 있었다. 또한, 침강장치 baffle의 각도를 변화시켜 슬러지 침강특성 영향을 분석한 결과 baffle 각도 20°에서 슬러지 계면층의 압축이 매우 높게 나타났다. 본 연구결과는 원형침전지의 침전 효율향상을 위한 기초 인자로 활용이 기대된다.

• Korean Chemical Engineering Research
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• 제49권4호
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• pp.491-497
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• 2011

본 연구에서는 CO, $H_2$가 주성분인 모사합성가스를 이용하여 합성천연가스(SNG, Synthetic Natural Gas) 제조공정을 평가하기 위하여, 3종류의 SNG 합성반응시스템을 제안하였다. 제시된 공정은 다단 단열반응시스템, 재순환이 있는 다단 단열반응시스템 그리고 강제냉각방식의 수냉각반응시스템이다. 3개의 연속된 반응기로 구성된 다단 단열반응시스템에서의 1차반응기에서는 온도가 최대 $800^{\circ}C$까지 상승하였으며, 이로 인한 수성가스전환반응으로 인해 $CO_2$가 다른 시스템에 비해 많이 생성되었으며, SNG 내의 $CH_4$ 농도는 90.1% 정도를 얻었다. 다단 단열반응시스템의 문제점을 해결하기 위해 재순환이 있는 다단 단열반응시스템에서는 반응기의 온도제어를 위해 일부 전환가스를 재순환한 것으로, $CH_4$는 최대 96.3%를 얻었다. 이러한 다수개의 반응기로 구성된 단열반응기의 단점을 해결하여 반응기 개수를 줄일 수 있는 쉘과 튜브 형태의 반응기로 구성된 강제냉각방식의 수냉각시스템에서는 쉘 측으로 냉각수를 공급하여 반응열을 흡수하는 형태로, 공급되는 냉각수의 유량과 압력에 의해 온도를 제어할 수 있다. 이 시스템에서는 최대 $CH_4$는 최대 99.2%를 얻었으며, 1차 반응기인 강제냉각방식의 수냉각반응기 출구에서의 97% 이상의 $CH_4$ 농도를 얻을 수 있음을 확인하였다.

• 한국전자통신학회논문지
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• 제12권6호
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• pp.989-996
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• 2017

제안된 지향성 펜슬빔 안테나는 절곡된 타원 도체평판을 갖는 도파관 급전부와 포물형 곡면 반사판으로 구성되어 있다. 반사판 뒤에서 삽입된 급전 도파관의 종단 부근 광벽에 위치한 두 개의 사각형 개구는 반사판 초점에 위치하며, 절곡된 타원 평판으로 전자파 에너지를 방출시킨다. 이 평판은 전자파 에너지를 일차 반사시키며, 주 반사판을 향하도록 설계되어 있다. 도파관 종단에 위치한 두 사각형 개구는 안테나 시스템의 임피던스 정합을 위해서 안쪽으로 돌출된 탭을 가지는데, 탭의 형태는 잘려진 타원형이다. 제안된 포물형 반사판 안테나의 반사판의 직경은 400 mm, 촛점은 134.23 mm 이며, 사용 중심주파수 16.5 GHz에서 안테나이득은 33.68 dBi, 3 dB 빔폭은 $3.3^{\circ}$, 반사손실 -15 dB 사용대역폭은 1.0 GHz 이상이 되도록 설계하여, HFSS-IE를 사용하여 검증하였다.