• Title/Summary/Keyword: Equilateral triangular channel

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Detailed Measurement of Heat/Mass Transfer in a Rotating Equilateral Triangular Channel with Smooth Walls (회전하는 매끈한 정삼각 유로 내 열/물질전달 분포 측정)

  • Kim, Kyung-Min;Lee, Dong-Hyun;Cho, Hyung-Hee
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.7 s.262
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    • pp.628-634
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    • 2007
  • The present study investigated the heat/mass transfer characteristics in an equilateral triangular channel simulating the leading edge cooling passage in gas turbine blade. Using naphthalene sublimation method and pressure measurement experiments, local mass (heat) transfer and pressure coefficients were obtained. The experiments were conducted with three rotating numbers between 0.0 and 0.1; two channel orientations of $0^{\circ}$ (model A) and $30^{\circ}$ (model B); the fixed Reynolds number of 10,000. The results showed that the channel rotation caused the heat transfer discrepancy between suction and pressure sides. Due to the secondary flow induced by Coriolis force, the high heat transfer appeared on the pressure side. When the channel orientation was $30^{\circ}$ (model B), the secondary flow caused the more uniform heat transfer distribution among leading edge and inner wall on pressure side than that of the model A.

Exergetic analysis for optimization of a rotating equilateral triangular cooling channel with staggered square ribs

  • Moon, Mi-Ae;Kim, Kwang-Yong
    • International Journal of Fluid Machinery and Systems
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    • v.9 no.3
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    • pp.229-236
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    • 2016
  • Exergetic analysis was introduced in optimization of a rotating equilateral triangular internal cooling channel with staggered square ribs to maximize the net exergy gain. The objective function was defined as the net exergy gain considering the exergy gain by heat transfer and exergy losses by friction and heat transfer process. The flow field and heat transfer in the channel were analysed using three-dimensional Reynolds-averaged Navier-Stokes equations under the uniform temperature condition. Shear stress transport turbulence model has been selected as a turbulence closure through the turbulence model test. Computational results for the area-averaged Nusselt number were validated compared to the experimental data. Three design variables, i.e., the angle of rib, the rib pitch-to-hydraulic diameter ratio and the rib width-to-hydraulic diameter ratio, were selected for the optimization. The optimization was performed at Reynolds number, 20,000. Twenty-two design points were selected by Latin hypercube sampling, and the values of the objective function were evaluated by the RANS analysis at these points. Through optimization, the objective function value was improved by 22.6% compared to that of the reference geometry. Effects of the Reynolds number, rotation number, and buoyancy parameter on the heat transfer performance of the optimum design were also discussed.

Numerical Study on Various Ribs in a Triangular Internal Cooling Channel (삼각형 내부냉각유로에 설치된 다양한 형태의 리브에 관한 수치해석적 연구)

  • Park, Min-Jung;Moon, Mi-Ae;Kim, Kwang-Yong
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.4
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    • pp.19-26
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    • 2012
  • In this paper, a parametric study on ribs which are installed in an equilateral triangular internal cooling channel is presented. The numerical analysis of the flow structure and heat transfer characteristics is performed using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The numerical results are obtained at Reynolds number, 20,000. The parametric study is performed for the parameters, the angle of a rib, rib pitch-to-hydraulic diameter ratio, rib width-to-hydraulic diameter ratio, and rib height-to-hydraulic diameter ratio. The computational results are validated with the experimental data for area-averaged Nusselt number.

Heat Transfer Characteristics in a Leading Edge Cooling Channel of a Turbine Blade with Various Rib Arrangements (터빈 기익 선단부에 설치된 냉각유로에서의 요철 배열에 따른 열전달 특성)

  • Lee, Dong-Hyun;Kim, Kyung-Min;Rhee, Dong-Ho;Cho, Hyung-Hee
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.459-466
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    • 2005
  • The present study investigates the heat transfer characteristics of a triangular channel. Three different rib configurations are tested. The ribs are installed on two sides of the channel. The rib height (e) to channel hydraulic diameter is 0.079 and the rib-to-rib pitch (p) is 8 times of the rib height. The rotation number ranges from 0.0 to 0.1 while the Reynolds number is fixed at 10,000. The copper blocks with heaters are installed on the channel walls to measure the regionally averaged heat transfer coefficients. For the stationary $45^{\circ}$ and $135^{\circ}$ ribbed channels, a pair of counter rotating vortices is induced by the angled rib arrangements, and high heat transfer coefficients are obtained on the regions near the inner wall for the $45^{\circ}$ ribbed channel and near the leading edge for the $90^{\circ}$ ribbed channel. The heat transfer coefficients of angled ribbed channels are changed little with rotation, whereas those of the transverse ribbed channel are changed significantly with rotation.

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