• Geomechanics and Engineering
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• 제17권2호
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• pp.133-143
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• 2019

An optimal hydraulic section is critical for irrigated water conservancy in seasonal frozen ground due to a large proportion of water leakage, as investigated by in-situ surveys. This is highly correlated with the frost heave of underlain soils in cold season. This paper firstly derived a practical model for frost heave of clayey soils, with temperature dependent thermal indexes incorporating phase change effect. A model test carried out on clay was used to verify the rationality of the model. A novel approach for optimizing the cross-section of irrigation canals in cold regions was suggested with live updated geometry characterized by three unique geometric constraints including slope of canal, ratio of practical flow section to the optimal and lining thickness. Allowable frost heave deformation and tensile stress in canal lining are utilized as standard in computation iterating with geometry updating while the construction cost per unit length is regarded as the eventual target in optimization. A typical section along the Jinghui irrigation canal was selected to be optimized with the above requirements satisfied. Results prove that the optimized hydraulic section exhibits smaller frost heave deformation, lower tensile stress and lower construction cost.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.465-472
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• 1999

Hydraulic model tests are performed to find economical and hdrqulically stable design of cooling water intake channel of steam power plant. The result of tests show that the standard distributiion of y-components in the chamber of CWP(circulating Water Pump) are recommended below 3.5 to maintain hydraulic stability, so that this value is considered as the design criteria. Common basin is necessary to improve the hydraulic stability of inflow, however the longer basin does not always improve the hydraulic stability , and the optimal length of basin can be found in some range. From the results the flow stability maintained the best condition when the length of basin is 7.2m. Beside the standard tests the auxiliary tests like edge , baffle, trapezoidal section and increase of pump capacity are carried out based on the optimal condition foudn in the standard tests. From the series of tests the economical and hydraulically stable design of intake channel was proposed.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1181-1190
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• 2023

Hydraulic performance and flow resistance tests were performed to confirm the main parameters of the hydraulic instrumentation that can affect the pump performance of the reactor coolant pump. The flow resistance test offers important experimental data, which are necessary to predict the behavior of the primary coolant when the circulation of the reactor coolant pump is stopped. Moreover, the shape of the hydraulic section of the pump, which was considered in the test, was prepared to compare the mixed-flow- and axial-flow-type models, the difference in the number of blades of the impeller and diffuser, the difference in the shape of the impeller blade and its thickness, and the effect of coating at the suction bell. Additionally, five models of the hydraulic part were manufactured for the experiments. In this study, the differences in performance owing to the design factors were confirmed through the experimental results.

• 한국생산제조학회지
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• 제19권6호
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• pp.776-781
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• 2010

Optimum design of movable hydraulic crane's booms for weight reduction was performed in this study. Since the boom weight of the present used booms is very heavy, it is needed to make them lighter structure as possible as we can. Optimum design was performed for the booms by changing from the hexagonal cross section to triangular truss structure under the conditions, which are the allowable stress for the present cross section must be maintained, and the optimized weight must be minimized. CATIAV5 was used for stress analysis and design variables were established as the height and width of the triangular truss structure. As the results, it is found that the height of the truss structure is increased in proportion to the height of the booms and the maximum stress for optimal truss structure was obtained as 412MPa, which is lower than the allowable stress for the present hexagonal cross section. The optimized weight of the booms is reduced to about 19.88% comparing to the original weight.

• 한국환경과학회지
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• 제8권1호
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• pp.95-100
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• 1999

Process intensification without any increase in bed requires the exploitation of fluid mechanical phenomena as the basis for elegant solutions to the process engineering problems which result from the need to retain and control the immobilized biomass, and for biomass recovery. The fluidized bed biological reactor provides a solution to these needs. The wastewater treatment characteristics of the fluidized bed was filled with sand media. Indirect aeration were studied experimentally. The researcher was filled with sand particle size(0.60~0.42mm) in three reactors with different section area(A)/height(H), in the state BOD loading 4.5kg-$BOD_5/m^3$ㆍd, and under the fixed state of hydraulic retention time for around 32 minutes.

• 한국터널지하공간학회 논문집
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• 제17권1호
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• pp.49-63
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• 2015

본 논문에서는 가상 해저터널의 세그먼트 라이닝의 부재력 평가하여 수심별 세그먼트 최적 두께 산정 및 하중식에 따른 부재력 변화에 관한 내용을 다루었다. 가상 해저터널의 세그먼트 부재력을 평가하기 위해 먼저 다양한 설계 조건을 도출하고 이에 대해 2-Ring Beam 모델을 이용한 구조해석을 수행하여 부재력을 산출하였다. 산출한 부재력을 이용하여 예비 철근 배근을 통해 단면검토를 수행하여 각각의 지층별로 철근 배근을 조절하여 최적 두께를 산정하였다. 검토 결과를 토대로 시공조건에 따른 부재력 변화 경향을 검토하였으며 아울러 다양한 시공조건에 따른 최적 라이닝 단면을 제시하였다.

• 한국농공학회논문집
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• 제49권5호
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• pp.11-20
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• 2007

In this study, we reviewed the optimal space for the fishway and fish storage establishment in the section between the downstream of the Hwacheon dam and the confluence of the Pungsan river. The hydraulic stability of these facilities was also examined. In the section between the downstream of Hwacheon dam and the confluence of Pungsan river, the release flow of Hwacheon dam was set at $5,495m^3/s,\;6,110m^3/s$ and $7,537m^3/s$, and numerical simulations were executed for each instance using the HEC-RAS model and RMA-2. In the analysis of the flow velocity distributions in the subject section by release flows of Hwacheon dam, it was shown that there was over 5.0m/s of high flow velocity at Sta. $#1{\sim}Sta.$ #3, Sta. $#4{\sim}Sta.$ #6, and Sta. $#12{\sim}Sta.$ #13 of the sections analyzed in this study. The Sta. $#0{\sim}Sta.$ #1 was considered appropriate for the fishway and fish storage establishment. As seen in the results of the numerical stability review by release flow conditions of Hwacheon dam subject to the selected available areas fur fishway and fish storage, the topographically available section for the establishment of fishway and fish storage exists at Sta. $#1{\sim}Sta.$ #3 when the release flow of Hwacheon dam is $5,495m^3/s$, whereas Sta. $#0{\sim}Sta.$ #1 should be reviewed for the subject section for the establishment of fishway at release flows of $6,110m^3/s$ and $7,537m^3/s$, in addition to the figures gathered at the $5,495m^3/s$ release flow. Finally, the available section for the establishment of fishway and fish storage was determined to be Sta. $#0{\sim}Sta.$ #3. Further, if fishway and fish storage are established in the outer bank within this section, the high flow velocity section should be avoided. An alternative would be to establish for the fishway in the inner band on the section of Sta. #1 or Sta. #3.

• 터널과지하공간
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• 제34권3호
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• pp.231-247
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• 2024

고심도 암반대수층이 운영시설의 주요 대상이 되는 고준위 방사성폐기물 처분 분야에서 수리특성 정보들은 관련 처분 부지 선택, 처분 시설 상세 설계, 최적 시공 방안 도출 그리고 운영 시 안정성 평가에 있어 가장 중요한 핵심 요소로 작용한다. 국내에는 좁은 면적에 여러 암종이 혼재되어 분포하고 있기 때문에 다양한 암종별 암반대수층의 수리지질특성을 분석하고 이를 데이터베이스화 하는 사전 작업들이 중요하다. 본 논문에서는 고심도 화산암반대수층의 현장 수리특성 중 가장 대표적인 수리전도도 자료를 획득하고 이를 분석 평가하였다. 현장 자료 획득을 위해 자체적으로 개발된 고성능 수리시험 장치를 활용하였고, 표준화된 시험법 및 조사절차를 적용하였다. 수리특성 자료분석 과정에서는 심도별로 수리상수인 수리전도도 값을 구하였으며, 시험 구간에 위치한 투수성 암반 절리를 통한 지하수 흐름 양상에 관해서도 평가하였다. 본 논문에서 제안된 일련의 자료 획득 방법, 절차와 분석 결과들은 국내 고심도 암반대수층의 수리특성 자료 데이터베이스 구축에 활용됨과 더불어 향후 다양한 지역별 암종별 수리특성연구에 적용될 기술적 노하우를 향상시키는 역할도 할 것으로 기대된다.

• 대한공간정보학회지
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• 제23권2호
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• pp.59-67
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• 2015

치수적 안전은 하천의 계획에 있어 가장 먼저 고려해야 할 사항이며 최근 폭넓게 진행 중인 하천의 복원에 있어서도 치수적 안전은 기본적인 전제조건이 된다. 안전한 하천의 계획은 정확한 측량자료로부터 시작된다. 본 연구에서는 스마트 지형공간정보를 이용하여 하천의 3차원 지형모델을 제작하고 제작된 3차원 지형모델을 이용하여 하천의 수리해석 및 하천 복원에 적용하였다. 이를 통해 상세한 하천 현황 데이터를 추출함으로써 보다 정확한 수리해석이 가능하였다. 또한, LiDAR 데이터를 도시하천의 수리해석에 이용할 경우 적용할 수 있도록 효율적인 데이터 처리와 수리해석의 정확성을 고려한 최적 횡단면 간격을 결정하였다. 하천 복원 설계를 위한 3차원 설계방안과 하천의 다양한 공간계획에 3차원 지형모델을 이용할 수 있는 활용 방안을 제시하였다.

• 한국산학기술학회논문지
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• 제15권1호
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• pp.506-514
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• 2014

최근 국내에서 도심지 홍수로 인한 피해 발생이 증가하면서 차집된 다량의 강우를 일시에 배출할 수 있는 와류 유입구에 대한 관심이 증가하고 있다. 이 중 접선식 유입구는 구조가 단순하고 크기가 작아 적용성이 높으나 설계 유량보다 작은 유량에 대해서 와류가 형성되지 못하는 단점이 있다. 본 연구에서는 이를 보완하여 새롭게 제안된 2가지 종류의 복단면형 접선식 와류 유입구의 수리 특성을 3차원 수치모의를 통해서 분석하였다. 기존에 제시된 한계수심 이론과 자유 배수 조건 이론을 이용하여 복단면 형상의 접선식 와류 유입구의 특성을 흐름 상태, 수면형, 수심-유량 관계, 공기 기둥 면적비 측면에서 분석하였다. 종합적인 수리 특성 분석 결과 완경사형 복단면 접선식 유입구가 최적안으로 판단되나 설계 유량이 작은 경우에는 급경사형 복단면도 가용한 것으로 나타났다.