• 한국산학기술학회논문지
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• 제20권4호
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• pp.639-647
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• 2019

최근 전자장비의 소형화 및, 고밀도화가 되는 반도체 집적기술의 발달로 인해 칩과 모듈에서 발생되는 내부발열량을 외부로 적절히 방출시키기 위해서 열 제어시스템 적용에 대한 연구의 중요성을 인식하고 있다. 본 연구는 SST k-${\omega}$ 난류모델을 적용하여 4개의 블록이 부착한 수평채널내에서 열전달 및 압력강하 특성을 고찰하였다. CFD 해석시 적용한 매개변수는 블록 폭, 블록 높이, 열원 및 난류발생기 배치이고, 해석시 기본 경계조건은 채널 입구의 온도 및 유속은 300 K, 3.84 m/s, 열유속은 $358W/m^2$으로 하였다. 그 결과로 블록 폭비율(w/h)이 증가할수록 열전달성능이 감소하는 반면에 블록 높이비(h/w)이 증가할수록 열전달특성은 증가하는 경향을 나타내었으며, 열원의 크기배열은 낮은 열유속에서 높은 열유속으로 증가시킬수록 열원의 영향을 받아 열전달계수는 증가하는 경향을 나타냈고, 난류발생기는 채널 입구에 가까운 블록 1번 위치의 상단에 설치했을 경우가 4개의 가열블록 전체에 가장 영향을 크게 미치게 되고, 압력강하특성을 고려할 때 가장 적절한 위치로 선정할 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.53.2-53.2
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• 2005

• Journal of Ship and Ocean Technology
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• 제3권2호
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• pp.1-16
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• 1999

The incompressible Reynolds-Averaged Navier-Stokes(RANS) equations are solved using the standard $\textsc{k}-\varepsilon$ turbulence model and a finite volume method(FVM)with an O-type grid system. The computed results for its performance test are in good agreement with the published experimental data. The present method is applied to the study on the leading edge radius of a hydrofoil section Calculated results suggest that the leading edge radius has some effects on cavitation performances of a 2-D foil. A natural leading edge radius for the NACA66 section is determined from this study.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.684-689
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• 2001

In this study, three-dimensional viscous flow analysis and optimization are presented for the design of a mixed-flow fan. Steady, imcompressible, three-dimensional Reynolds averaged Navier-Stokes equations are used as governing equations, and standard $k-{\varepsilon}$ turbulence model is chosen as a turbulence model. Governimg equations are discretized using finite volume method. Upwind difference scheme is used for the discretization of the convective term and SIMPLEC algorithm is used as a velocity-pressure correction procedure. The computational results are compared with the results obtained by TASCflow. For the numerical optimization of the design, objective function is defined as a ratio of generation of the turbulent energy to pressure head. Sweep angles are used as design variables.

• 한국추진공학회지
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• 제8권1호
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• pp.16-26
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• 2004

본 연구의 목적은 예조건화 방법론을 난류모델을 포함한 Navier-Stokes 방정식에 적용하는 것이다. 가상 음속 개념을 적용하였다 공간차분을 위해 Roe의 FDS를 사용하였고, 시간 적분을 위해 LU-SGS 기법을 사용하였다. 알고리즘을 검증하기 위하여 NACA 날개 주위의 저속유동, 초음속 노즐 유동을 계산하였다. 본 연구에서 개발된 알고리즘은 저속유동 및 초음속 유동의 계산에서 충분한 계산 성능을 보이는 것으로 판단된다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.202-207
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• 2009

본 연구에서는 대심도 지하역사에서 화원 위치에 따른 연기거동의 특징을 분석하였다. 전산수치해석에 FDS code가 사용되었다. 화재에 의한 유체거동을 모사하기 위하여 난류모델은 LES를 사용하였으며, 빠른 계산을 수행하기 위하여 병렬수치해석기법을 사용하였다. 본 연구를 통하여 대심도 역사에서 화재시 피난을 저해하는 화원의 위치에 대하여 검토하였다.

• 한국전산유체공학회지
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• 제8권2호
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• pp.49-56
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• 2003

Three-dimensional endwall flow within a linear cascade passage of high performance turbine blade is simulated with a 3-D Navier-Stokes CFD code (MOSA3D), which is based on body-fitted coordinate system, pressure-correction and finite volume method. The endwall flow characteristics, including the development and generation of horseshoe vortex, passage vortex, etc. are clearly simulated, consistent with the generally known tendency. The effects of both turbulence model and convective differencing scheme on the prediction performance of endwall flow are systematically analyzed in the present paper. The convective scheme is found to have stronger effect than the turbulence model on the prediction performance of endwall flow. The present simulation result also indicates that the suction leg of the horseshoe vortex continues on the suction side until it reaches the trailing edge.

• 한국전산유체공학회지
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• 제8권2호
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• pp.8-15
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• 2003

Three nonlinear κ-ε models with the wall function method are applied to the fully developed turbulent flow in a triangular subchannel of a bare rod bundle. Typical predicted quantities such as axial and secondary velocities, turbulent kinetic energy and wall shear stress are compared in details both qualitatively and quantitatively with both each other and experimental data. The nonlinear κ-ε models by Speziale[1] and Myong and Kasagi[2] are found to be capable of predicting accurately noncircular duct flows involving turbulence-driven secondary motion. The nonlinear κ-ε model by Shih et aL.[3] adopted in a commercial code is found to be unable to predict accurately noncircular flows with the prediction level of secondary flows one order less than that of the experiment.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.439-443
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• 2002

In this study, three-dimensional incompressible viscous flow analysis and optimization using response surface method are presented for the design of a jet fan. Steady, incompressible, three-dimensional Reynolds averaged Wavier-Stokes equations are used as governing equations, and standard k-$\epsilon$ turbulence model is chosen as a turbulence model. Governing equations are discretized using finite volume method. Sweep angles and maximum thickness of blade are used as design variables for the shape optimization of the impeller in response surface method. The experimental points which are needed to construct response surface are obtained from the D-optimal design and Full Factorial design and relations between design variables and response surface are examined.

• 한국전산유체공학회지
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• 제6권2호
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• pp.40-46
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• 2001

Two-dimensional steady flowfields generated by slot injection into supersonic flow are numerically simulated by the integration of Navier-stokes equation with two-equation κ-turbulence model. High-order upwind scheme is used on unstructured adaptive meshes. The numerical results are compared with experimental data in terms of surface static pressure distributions, the length of the upstream separation region, and the height of the Mach surface for steady flowfields with a Mach number of 3.71 and a unit Reynolds number of 5.83×10/sup 6//m.