• Title/Summary/Keyword: CFD 수치해석

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Numerical Study of Breakup Process of Diesel Spray (디젤분무의 분열과정에 대한 수치해석 연구)

  • Yeom, Jeong Kuk;Jung, Woo Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.12
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    • pp.1489-1495
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    • 2013
  • High-pressure flows are ubiquitous in many industrial fields. A representative application is fuel injection using a common-rail control system in diesel engines, where the injection pressure in the injector exceeds 1000 bar. In high-speed injection, the fluid injected through the nozzle undergoes breakup owing to the interaction with the ambient gas. The breakup process influences mixture formation, which in turn influences combustion in diesel engines. Therefore, it is very important to analyze the breakup process of fuel spray. The Reitz and Diwakar model and cascade atomization and breakup (CAB) model were used in this study as sub-models for the numerical analysis of the breakup process of fuel spray. This study aims to precisely analyze the breakup process of spray and to investigate the breakup frequency of the injected fuel. Consequently, it proposes a suitable sub-model for analyzing the breakup process of a diesel spray by using CFX, a commercial CFD program.

Computational Fluid Dynamic Analysis for Improving the Efficiency of Desulfurization System for the Wet Flue Gas (습식 배연탈황 시스템의 효율 향상을 위한 전산해석)

  • Hwang, Woo-Hyeon;Lee, Kyung-Ok
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.2
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    • pp.161-171
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    • 2014
  • In this paper the flow dynamics of the flue gas equipment in the desulfurization system was numerically analyzed by simulating the problems for the turbulent and combustion flow from Induced Draft Fan(I.D.Fan) outlet to Booster Up Fan(B.U.Fan) inlet using the commercial CFD software of CFD-ACE+ in CFDRC company for Computational Fluid Dynamic Analysis. The guide vane of this section was examined for the minimum pressure loss and the uniform flow dynamic to B.U.Fan with the proper velocity from I.D,Fan exit to B,U,Fan inlet section at the boiler both the maximum continuous rating and the design base. The guide vanes at I,D.Fan outlet and B.U.Fan inlet were removed and modified by numerical simulation of the CFD analysis. The flue gas at the system had the less pressure loss and the uniform flow dynamics of the flow velocity and flow line by comparing with the old design equipment.

CFD Prediction on Vortex in Sump Intake at Pump Station (펌프 흡수정내 발생된 보텍스에 대한 CFD 예측)

  • Park, Sang-Eun;Roh, Hyung-Woon
    • The KSFM Journal of Fluid Machinery
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    • v.10 no.4
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    • pp.39-46
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    • 2007
  • In large pump station, vortex generation such as free-surface vortex and submerged vortex occurring around pump intake, or at bell-mouth inlet has been an important flow characteristics which should be considered always to keep away the suction of air-entrained or cavitated flow. In this study, a commercial CFD code was used to predict accurately the vortex generation for the specified intake design. These result shows the preliminary result of submerged vortex prediction for the Turbo-machinery Society of Japan Sump Test CFD standard model. At bottom wall, air volume fraction (red color) was found in a large scale to explain the submerged vortex generation at particular operation and configuration condition. And these indicate the free surface formation behind the bell mouth. Particularly, non-uniform approaching flow is a major parameter to govern the occurrence of the free-surface vortex. Futhermore the comparison between turbulence ($k-{\epsilon}$ & $k-{\omega}$ model) mode were executed in this study.

CFD를 이용한 청항선 해상부유물 프로펠러 유입 가능성 검토

  • Lee, Gyeong-Wan;Kim, Byeong-Jae;Lee, Jun-Hyeong;Yu, Gwang-Yeol
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2018.11a
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    • pp.212-213
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    • 2018
  • 청항선은 해상 부유물을 수거하는 배로서 청소과정에서 특성상 해상부유물로 인한 선체손상 또는 프로펠러 유입으로 사고의 위험이 있다. 따라서, 건조 시 이를 고려한 설계를 하거나 반영하여야 한다. 그러나 모형시험에서 구현의 문제와 많은 Case로 인해 시간과 비용에 많은 어려움이 있다. 따라서, 이를 예측하기 위해 최근 발전하고 있는 수치해석을 통해 해상 부유물을 구현하였다. 그 후 속도에 따라 부유물을 흘려 프로펠러 주변 유입여부를 확인하였다.

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Interference Effects of Neighboring Structures on Wind Pressure (인접 구조물의 상호 간섭 효과 해석)

  • Park, Sang-Jun;Lee, Seung-Un;Lee, Seung-Su
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.574-578
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    • 2014
  • 본 연구에서는 인접 구조물의 상호 간섭에 의한 풍압 변화에 대한 분석을 수행하였다. 두 개의 구조물 사이의 거리 및 위치를 변경하여 비교 해석하는 것으로써 사각형 구조물 구현을 위해 EDISON_CFD를 이용하여 수치해석을 하였고, 유한 체적 법(Finite Volume Method, FVM) 기반의 범용 비압축성 유동 해석을 위해 2D_Incomp-P_2.1 해석자를 사용하였다. 이 연구를 통하여 인접한 구조물의 영향을 분석하여 상호 간 거리와 위치를 결정할 수 있는 근거자료를 확보하였다.

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A Study on Flow Characteristics about Valve Filter for Electronic System Solenoid Structure (차량용 전자식 솔레노이드 밸브 필터간의 유동특성에 관한 연구)

  • Kim, Byeong-Jun;Cho, Haeng-Muk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.3
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    • pp.1294-1298
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    • 2014
  • Comparative analysis study of the flow characteristics and the experiment was done to try to present the orientation of the solenoid structure to be produced in the future. The comparative analysis of the analysis and experimental values was performed using the experiments and ANSYS CFD. 3D modeling of the structure are designed by the CATIA V5R18, meshing process of the flow section was used by ICEM CFD program. Flow rate was indicated by using the experimental values appear in $0-10{\ell}/min$, the result of the flow analysis, was $0.18{\ell}/min$ Max. It was possible to suggest a solenoid structure more efficient through comparative analysis of experimental values and flow analysis.

Two-Dimensional Numerical Study of Starting Process of a Ethylene Fueled Direct-Connect Scramjet Engine Combustor (에틸렌을 연료로 하는 Direct-Connect 스크램제트 엔진 연소기의 2차원 수치 해석)

  • Noh, Jin-Hyeon;Choi, Jeong-Yeol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.569-572
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    • 2009
  • The numerical simulations of hydrocarbon fueled scramjet engine have been studied less than them of hydrogen fueled scramjet engine. Ethylene is selected in hydrocarbon because of its good thermochemical properties and a direct-connect scramjet combustor at the American Air Force Research laboratory is taken to a two-dimensional simulation model. Ignition time delay of ethylene was monitored and air throttling was imposed to generate ignition inside the model scramjet.

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A Study for Improving the Performance of Savonius Wind Turbine (사보니우스 풍력 터빈의 효율 향상을 위한 연구)

  • Hong, Cheol-Hyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.2
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    • pp.258-263
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    • 2011
  • This study is aimed at obtaining basic design data for Savonius wind turbine, available in the domestic wind environments. To the end, the flow field characteristics around the wind turbine attached with 1/4 wind shield were monitored along with numerical analysis. On the top of this, numerical analysis and experiments on the rpm of the turbine rotor were conducted. As a result, this study found that the numerical analysis results squares with the experiment results and the rpm improves by over 70%.