• Title, Summary, Keyword: 입구 부

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Explicit Analysis of Flows in Box Culvert (사각형 암거흐름의 양해적 해석)

  • Yoo, Dong-Hoon;Uhm, Ho-Sik
    • Journal of Korea Water Resources Association
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    • v.36 no.3
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    • pp.481-494
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    • 2003
  • Flow through the culvert is very complex depending on the characteristics of hydraulic conditions. A design method using a monograph is normally employed due to the wide range of flow characteristics and the difficulty of calculating inlet water depth. The present study suggests the method for determining the inlet water depth of box culvert using Bernoulli's equation. By employing the explicit equation of inlet water depth, a standard design method of box culvert is developed for a wide range of flow characteristics. Explicit solution techniques are proposed to determine the width and height, slope and discharge of box culvert.

A Study on the Performance Prediction Method for an Axial Compressor with Variable Inlet Guide Vane (가변 입구 안내익이 있는 축류압축기의 성능예측 방법에 관한 연구)

  • Kim, Dong-Hyun;Kim, Sang-Jo;Kim, Kui-Soon;Son, Chang-Min;Kim, You-Il;Min, Seong-Ki
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.4
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    • pp.1-8
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    • 2012
  • In this study, numerical method, stage stacking method based on the result of numerical method and scaled stage stacking method have been applied to predict the performance of a multi-stage axial compressor with inlet guide vane. The results obtained through three different methods for off-design conditions were compared with performance test data. And the effect the angle of variable inlet guide vane was also investigated. The three-dimensional numerical simulation has been performed by using flow analysis program, $FLUENT^{TM}$ 6.3 and the performance prediction based on the stage stacking method has been performed with compressor analysis code from NASA.

Investigation of Flow and Heat Transfer Characteristics of Plate Heat Exchanger Taking into Account Entrance Effects and Variation in Corrugation Height (입구영향 및 주름높이의 변화를 고려한 판형열교환기의 유동 및 열전달 특성)

  • Moh, Jeong-Hah
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.11
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    • pp.965-973
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    • 2010
  • Numerical analysis has been carried out to investigate the heat transfer characteristics of a plate heat exchanger. The multi-cell models with inlet part and outlet part are used for performing numerical simulation. The plate heat exchanger is characterized by chevron angle of $15^{\circ}$, corrugation pitch of 24mm and corrugation height 6~12mm. The length of the inlet-part considered in the analysis ranges from 24.8 to 124mm and Reynolds numbers range from 1,000 to 10,000. The correlations such as friction factor and Colburn factor are compared with previous experimental data. The results can be utilized for designing the plate heat exchanger.

Esophagus and Pharynx reconstruction for head & Neck cancer (두경부암종에서 식도와 인두의 재건)

  • Son, Jin-Ho
    • Korean Journal of Bronchoesophagology
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    • v.11 no.2
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    • pp.10-15
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    • 2005
  • 식도와 인두 재건은 연하작용을 원활하게하고 발선기능을 보존하면서 위험부담이 가장 절은 술식을 선택하는 것이 원칙이다. 술식의 선택에 고려되어야 할 주요 인자는 결손부위의 크기, 창상의 상태, 술전 방사선치료 여부, 환자의 전신상태 등이다. 부분인두결손에는 유경근피판(pedicled myocutaneous flap)이나 유리피판이 적합하며 방사선 치료를 받은 경우는 유리피판이 유리하다. 흉곽입구 상부에 국한된 인두와 식도의 전체둘레결손에는 전완부, 외측 대퇴부, 공장의 유리피판이 좋다. 전완부는 피판이 다루기 쉽다는 장점이 있지만 공여부에 합병증이나 미용상의 문제가 있고 외측 대퇴부는 공여부의 문제는 매우 적으나 피판의 사용이 전완부에 비하여 약간 제한적이다. 공장은 허혈에 약하고 공여부 합병증이 다른 피판에 비해 불리하다. 저자의 경험으로는 흉곽상부에 국한된 결손의 재건에 환자가 비만하거나 대퇴부에 털이 많은 경우는 전완부 유리피판이 좋고 그렇지 않으면 외측 대퇴부 유리피판을 선택하는 것이 좋다고 생각된다. 흉곽입구 하방까지 연장된 결손이나 식도전적출술로 인한 결손에는 위전위술이 가장 적합하다. 방사선치료 등으로 창상에 혈관보호가 요구되는 경우는 대흉근피판이 유용하다. 앞으로 새로운 재건술의 개발이 이어지겠지만 모든 환자에게 맞는 이상적인 재건술은 없다. 재건술마다의 장단점과 제약점을 파악하고 환자의 조건에 따라 가장 적절한 재건술을 선택하는 것이 중요하다.

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어류 이동의 효율성을 고려한 어도 설계

  • Kim, Jin-Hong
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.2000-2004
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    • 2008
  • 본 지침은 하천 횡단시설물을 설치하는 경우, 효율적인 어류 이동을 위한 어도 설계 및 설치 기법을 제시함에 있다. 어도의 설계 조건으로는 상류 이동 어류가 어도입구 이외의 장소에 모여들지 않아야 하고, 이동 어류의 손상이나 극도의 피로를 피하도록 하여야 하며, 어도의 입구에 모인 어류의 어도로의 유인이 용이하여야 한다. 또한 어류가 쉽고 안전하고 신속하게 상류 이동할 수 있어야 한다. 주요 내용으로, 어도의 하류측 돌출 조건, Set back식 어도, 하류 턱 설치, 어도의 하류 끝단의 설계, Notch부의 단면 형상, 어도의 접속 조건, 로프 설치 조건, 어도의 하류부 설치 기법, 강하용 어도의 설계 기법 등을 제시하였다.

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The improvement of Two-Dimensional Subsonic Diffuser Performance Using the Turbulent Wake Caused by Cylinder (실린더 후류를 이용한 2차원 디퓨저 성능개선)

  • Kim, Se-Il
    • Proceeding of EDISON Challenge
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    • pp.614-618
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    • 2014
  • 본 연구에서는 디퓨저의 압력회복을 높이기 위해 디퓨저 입구에 실린더를 설치하여 후류가 압력회복에 어떤 영향을 미치는지 알아보았다. 2D-Incomp-2.1-P 해석자를 이용하여 속도, 압력에 따른 유동가시화를 통해 내부유동을 분석하였고, 압력회복계수를 비교하여 디퓨저 입구에 설치된 실린더의 후류가 디퓨저 성능에 어떤 영향을 주는지 비교하였다. 그결과 실린더를 설치하였을 때 확대부에서의 박리영역이 더 작아졌고 압력회복계수가 더 높아졌다.

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Shape Optimization of Inlet Part of a PCHE (인쇄형 열교환기 입구부의 최적설계)

  • Koo, Gyoung-Wan;Lee, Sang-Moon;Kim, Kwang-Yong
    • The KSFM Journal of Fluid Machinery
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    • v.16 no.2
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    • pp.35-41
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    • 2013
  • Inlet part of a printed circuit heat exchanger has been optimized by using three-dimensional Reynolds-Averaged Navier-Stokes analysis and surrogate modeling techniques. Kriging model has been used as the surrogate model. The objective function for the optimization has been defined as a linear combination of uniformity of mass flow rate and the pressure loss with a weighting factor. For the optimization, the angle of the inlet plenum wall, radius of curvature of the inlet plenum wall, and width of the inlet pipes have been selected as design variables. Twenty six design points are obtained by Latin Hypercube Sampling in design space. Through the optimization, considerable improvement in the objective function has been obtained in comparison with the reference design of PCHE.

A CFD Analysis of Flow Velocity at Inlet of a Diesel Particulate Filter according to the Curved Duct Connection Conditions (곡관 연결 조건에 따른 디젤엔진 매연여과장치 입구 유속 분포의 CFD 해석)

  • Lee, Su-Rvong;Ko, Young-Narn;Lee, Choong-Hoon
    • Journal of the Korean Society for Railway
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    • v.12 no.4
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    • pp.457-464
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    • 2009
  • The now velocity distribution at inlet of diesel Particulate filter (DPF) which is connected to each curved duct was simulated using $STAR-CD^{(R)}$. Three kinds of models which describe the shapes of the curved duct ware used for the CFD simulation. The simulation results were compared with the experimental data of velocity distribution which was obtained using a Pitot tube and 2-D positioning machine. At the $90^{\circ}$ curved connecting condition, the CFD simulation results of flow velocity distribution at inlet of the DPF showed a horse hoop shape shifted from the axial center line of the DPF. The CFD simulation results agree reasonably with those of the experiments.

Opening Characteristics of a Main Oxidizer Shut-off Valve at Different Valve Inlet Pressures (밸브 입구 압력 변화에 따른 연소기 산화제 개폐밸브 열림 특성)

  • Hong, Moongeun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.10
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    • pp.801-807
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    • 2020
  • Opening characteristics of a main oxidizer shut-off valve at different valve inlet pressures have been experimentally investigated. The pilot pressure at the moment of the valve opening increases linearly with increasing the valve inlet pressure and the increased pilot pressure reduces the valve travel time. As the pilot pressure increases at the moment of valve opening, the time to start opening the valve is delayed resulting in increasing the valve opening time. With the increment of the valve inlet pressure, the valve opening time is mainly determined by the time required for the pilot pressure to start opening the valve. Therefore the design of a pilot gas supply system can readily control the valve inlet pressure at the valve opening as well as the amount of oxidizer supplied to a combustion chamber during the engine startup.

The Air Flow Measurement and Prediction of Pressure Loss at Engine Inlet Duct (엔진 입구 덕트에서 공기유량 측정 및 압력손실 예측방법)

  • Lee, Bo-Hwa;Yang, In-Young;Yang, Soo-Seok
    • Aerospace Engineering and Technology
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    • v.6 no.2
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    • pp.29-34
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    • 2007
  • The purpose of this paper was to address the methodology of the air flow measurement using duct mach number that was considered area-weighed average obtained by total pressure and temperature measured at engine inlet duct. Without installing boundary rake, the prediction of air flow measurement was discussed. Actual air flow measurement and pressure value using pressure loss through inlet seal were described to improve the reliability and operability of altitude engine test facility.

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