• 제목/요약/키워드: Ribbed Square Channel

검색결과 22건 처리시간 0.029초

거친 사각채널에서 열전달과 유체유동 특성에 관한 실험 및 수치해석 (Experimental and Numerical Investigation on Heat Transfer and Fluid Flow Characteristics in the Ribbed Square Channel)

  • 강호근;배성택;이대희;안수환
    • Journal of Advanced Marine Engineering and Technology
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    • 제30권2호
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    • pp.275-283
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    • 2006
  • Experiment and three dimensional numerical investigations of incompressible turbulent flow through square channels with one- and two-sided ribbed walls are performed to determine pressure drop and heat transfer. The CFX(version 5.7) software package is used for the computation. The ribbed walls have a $45^{\circ}$ inclined square rib. Uniform heat flux is maintained on whole inner heat transfer channel area. The numerical results coincide with experimental data that obtained for $7,600{\le}Re{\le}24.900$, the pitch-to-rib height ratio (p/e) of 8.0. and the rib height-to-channel hydraulic diameter ratio ($e/D_h$) of 0.0667. The results show that values of local heat transfer coefficient and friction factor in the channel with two-sided ribbed wall are higher than those in the channel with one-sided ribbed walls.

An Experimental Studies on Heat Transfer and Friction Factor in a Square Channel with Varying Number of Ribbed Walls

  • Oh Se-Kyung;Kim Won-Cheol;Ahn Soo-Whan;Kang Ho-Keun;Kim Myoung-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • 제29권3호
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    • pp.281-289
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    • 2005
  • An experimental study on the heat transfer and friction characteristics of a fully developed turbulent air flow in a square channel with $45^{\circ}$ inclined ribs on one, two, and four walls is reported. Tests were performed for Reynolds number ranging from 7,600 to 24,900. The pitch-to-rib height ratio, p/e, was kept at 8 and rib height-to-channel hydraulic diameter ratio, $e/D_h$, was kept at 0.0667. The heat transfer coefficient and friction factor values were enhanced with the increase in the number of ribbed walls. Results of this investigation could be used in various applications of internal channel turbulent flows involving different number of roughened walls.

$45^0$의 rib이 설치된 채널에서의 열전달과 유동특성의 실험 및 수치해석 (Experimental & Numerical Investigation for Heat Transfer and Flows in a $45^0$ Inclined Ribbed Square Channel)

  • 강호근;안수환;김명호
    • 한국마린엔지니어링학회:학술대회논문집
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    • 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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    • pp.178-179
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    • 2005
  • Numerical and experimental investigation of incompressible turbulent flow and heat transfer through square channels with varying number of ribbed walls were conducted to determined pressure drop and heat transfer. The CFX solver used for the computation. The rough walls have a $45^0$ inclined square rib. Uniform heat flux is maintained on whole inner heat transfer channel area. The numerical results agreed well with experimental data that obtained for 7600$D_h$) of 0.0667. The results show that values of local heat transfer coefficient and friction factor increase with an increasing number of ribbed walls.

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Heat Transfer and Friction in Rectangular Convergent Channels with Ribs on One Wall

  • Kim, Won-Cheol;Lee, Myung-Sung;Bae, Sung-Taek;Ahn, Soo-Whan
    • 동력기계공학회지
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    • 제18권2호
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    • pp.12-18
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    • 2014
  • The local heat transfer of developed turbulent flows in the stationary ribbed rectangular convergent channels has been investigated experimentally. The rectangular convergent channels with one ribbed surface only have the inclination of $0.72^{\circ}$ and $1.43^{\circ}$ at which the ribbed wall is manufactured with a fixed rib height (e) of 10 mm and the ratio of rib spacing (p) to height (e) =10. The measurement was conducted within the range of Reynolds numbers from 15,000 to 89,000. The local heat transfer characteristics of the rectangular convergent channels are quite different from those of the ribbed square straight channel.

사각 또는 반원 형상의 요철이 설치된 채널 내부의 유동 및 열전달의 큰에디모사 (Large Eddy Simulation of Flow and Heat Transfer in a Channel Roughened by Square or Semicircle Ribs)

  • 안준;최해천;이준식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1436-1441
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    • 2004
  • The internal cooling passage of a gas turbine blade can be modeled as a ribbed channel. Most studies have considered square ribs. However, the ribs can be rounded due to improper manufacturing or wear during the operation. Hence, we have studied two different rib geometries in this study, i.e. square and semicircle ribs. We have performed large eddy simulations (LES) and experiments to validate the results from the simulations. LES predicts the detailed flow and thermal features, which have not been captured by simulations using turbulence models. By investigating the instantaneous flow and thermal fields, we propose the mechanisms for the local heat transfer distribution between ribs. For both the geometries, heat transfer is enhanced by the entrainment of the cold fluid by the vortical motions and impingement of the entrained cold fluid on the ribs.

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채널 내 주기적으로 배열된 요철 형상이 난류 유동장/온도장에 미치는 영향 연구 (Analysis of the Turbulent Heat/Fluid Flow in a Ribbed Channel for Various Rib Shapes)

  • 최도형;유동렬;한유신
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2002년도 춘계 학술대회논문집
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    • pp.128-133
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    • 2002
  • The heat transfer characteristics of a turbulent flow in a ribbed two-dimensional channel have been investigated numerically. The fully elliptic governing equations, coupled with a four-equation turbulence model, $\kappa-\omega-\bar{t^2}-\epsilon_t$, are solved by a finite volume method of SIMPLE type. Calculations have been carried out for three rib cross-sections : square, triangular, and semicircular, with various rib pitches and Reynolds numbers. The procedure appears to be satisfactory as the results for the square rib compare favorably with available experimental data and earlier calculation. The optimal rib pitch that yields the maximum heat transfer has been identified. It is also found that the square rib is most effective in enhancing the heat transfer. The semicircular rib, on the other hand, incurs the least amount of pressure drop but the improvement in heat transfer is substantially lower.

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2벽면 확대 사각채널에서 리브 피치가 열전달과 마찰계수에 미치는 효과 (Effect of Rib Pitch on Heat Transfer and Friction Factor in a Two Wall Divergent Channel)

  • 안수환;이명성;정성수;배성택
    • 설비공학논문집
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    • 제26권4호
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    • pp.175-180
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    • 2014
  • Experimental investigations of the heat transfer and friction factors in the ribbed divergent rectangular channel with the channel exit hydraulic diameter to inlet hydraulic diameter ratio of 1.16 were performed. The surface heaters were mounted onto the two opposite walls. The main experimental parameter is the ratio of rib pitch (p) to height (e), at which the ratios (p/e) of 6, 10, and 14 are considered in the channel with ribs on one wall only. The straight ribbed square channel is also considered as a comparison. The major findings are that the ratio of p/e = 6 shows the highest values in the heat transfer and the ratio of p/e = 10 indicates the greatest friction factor in the ribbed divergent channel. Editor's note:No major changes or corrections needed. Well written.

한면에 리브가 설치된 4벽면 수축/확대 채널의 난류 열전달과 유체마찰 (Turbulent Heat Transfer and Friction in Four-Wall Convergent/Divergent Square Channels with One Ribbed Wall)

  • 안수환;이명성
    • 대한기계학회논문집B
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    • 제39권10호
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    • pp.773-778
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    • 2015
  • 가스터빈 냉각 장치인 블레이드 등과 같은 산업 설계를 개선하기 위해 사각 수축 및 확대채널에서 축방향의 거리에 따라 국부 난류 열전달과 압력강하에 대해 실험적으로 조사하였다. 수축 및 확대채널의 한 면에만 리브($10mm{\times}100mm{\times}5mm(t)$)를 연속적으로 배치하였고 충돌 각은 $90^{\circ}$로 피치(p)/높이(e)의 비는 10이 되도록 하였다. 수축채널의 수력직경비($D_{ho}/D_{hi}$)는 0.75, 확대채널의 수력직경비는 1.33 그리고 직선채널은 1.00이다. 열성능 비교를 위해 3가지 보편적인 제약 조건을 채택 하였다. 즉 동일 유량, 동일 펌프 동력 그리고 동일한 압력 강하이다. 3가지 조건모두 확대 채널에서 우수한 열 성능을 보였다.

채널회전 및 유출유동이 90도 요철이 설치된 사각채널 내 열/물질전달 특성에 미치는 영향 (Effect of Channel Rotation and Bleed Flow on Heat/Mass Transfer Characteristics in a 90° Ribbed Square Channel)

  • 박석환;전윤흥;김경민;이동현;조형희
    • 대한기계학회논문집B
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    • 제31권1호
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    • pp.83-90
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    • 2007
  • The present study investigated the effects of channel rotation and bleed flow on heat/mass transfer in a $90^{\circ}$ ribbed square channel. The bleed holes were located between the rib turbulators on the leading surface and those on the trailing surface case by case. The tests were conducted under the conditions of various bleeding ratios (0.0, 0.2, 0.4) and rotation numbers (0.0, 0.2, 0.4) at Re=10,000. The results suggested that heat/mass transfer characteristics were influenced by the Coriolis force, bleed flow and bleed hole location. The heat/mass transfer on the surface with bleed flow was more increased than that without bleed flow but that on the opposition surface was decreased. Those were due to the effects of the tripping flow and the diminution of main flow rate respectively. The results also showed that the heat/mass transfer characteristics were different according to bleed hole location and channel rotation.

Characteristics of Heat Transfer in the Ribbed Rectangular Channel with Variable Heating Condition

  • Kim Won-Cheol;Putra Ary Bachtiar Krishna;Kang Ho-Keun;Ahn Soo-Whan
    • International Journal of Air-Conditioning and Refrigeration
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    • 제15권1호
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    • pp.10-16
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    • 2007
  • Surface heat transfer of a fully developed turbulent air flow in a $45^{\circ}$ inclined ribbed square duct with two and four heating walls was experimentally investigated, at which the experimental works were performed for Reynolds numbers ranging from 7,600 to 24,900. The pitch-to-rib height ratio, p/e was kept at 8 and rib-height-to-channel hydraulic diameter ratio, $e/D_h$ was kept at 0.0667. The channel length-to-hydraulic diameter ratio, $L/D_h$ was 60. The heat transfer coefficient values were decreased with the increase in the number of heating walls. Results of this investigation could be used in various applications of internal channel turbulent flow involving roughened walls.