### 摘要

Two pairs of detailed Nusselt number (Nu) distributions on leading (LE) and trailing (TE) endwalls together with the Fanning friction factors (f) of a rotating two-pass parallelogram channel enhanced by the detached transverse ribs are simultaneously measured under forward and backward rotations. The tested Reynolds number, rotating number, density ratio, and buoyancy number are respectively in the ranges of 5,000<Re<15,000, 0<Ro<0.3, 0.044<Δρ/ρ<0.2, and 0<Bu<0.142. Due to the accelerating flows through the gaps between the detached ribs and channel endwalls, the transverse high Nu stripe emerges along the projection area of each detached rib on both static and rotating smooth endwalls. The disparities in the relative directions between Coriolis forces and channel periphery that restrains Coriolis flows at forward and backward rotations cause different heat transfer properties on the two pairs of rotating LE and TE. The area-averaged leading and trailing Nusselt numbers at forward rotations are 0.69-1.77 and 0.85-1.98 relative to the static-channel Nusselt number references (Nu0) respectively. With backward rotations, the ratios of regionally averaged Nusselt numbers between rotating and static channels for leading and trailing walls fall in the respective change to 0.86-2 and 0.91-1.76. At both forward and backward rotations, all the f factors over LE and TE are elevated from the static-channel levels (f0) and increased by increasing Ro. Channel averaged f/f0 ratios are respectively raised to 1.21-2.21 and 1.21-2.1 at forward and backward rotations. As the heat transfer enhancements attributed to the presence of detached transverse ribs taking precedence of the accompanying f augmentations, all the thermal performance factors (TPF) are above unity in the range of 1.26-2.94. Relative to the similar rotating two-pass parallelogram channel with attached 90^{0} ribs, the detached ribs generate the higher degrees of heat transfer enhancements with the larger extents of f augmentations.

原文 | English |
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主出版物標題 | Heat Transfer |

發行者 | American Society of Mechanical Engineers (ASME) |

卷 | 5A-2018 |

ISBN（列印） | 9780791851081 |

DOIs | |

出版狀態 | Published - 2018 一月 1 |

事件 | ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018 - Oslo, Norway 持續時間: 2018 六月 11 → 2018 六月 15 |

### Other

Other | ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018 |
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國家 | Norway |

城市 | Oslo |

期間 | 18-06-11 → 18-06-15 |

### 指紋

### All Science Journal Classification (ASJC) codes

- Engineering(all)

### 引用此文

*Heat Transfer*(卷 5A-2018). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2018-75278

}

*Heat Transfer.*卷 5A-2018, American Society of Mechanical Engineers (ASME), ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018, Oslo, Norway, 18-06-11. https://doi.org/10.1115/GT2018-75278

**Influence of rotating directions on hydro-thermal characteristics of a two-pass parallelogram channel with detached transverse ribs.** / Liou, T. M.; Huang, C. Y.; Lan, I. A.; Chan, S. P.; Chang, Shyy-Woei.

研究成果: Conference contribution

TY - GEN

T1 - Influence of rotating directions on hydro-thermal characteristics of a two-pass parallelogram channel with detached transverse ribs

AU - Liou, T. M.

AU - Huang, C. Y.

AU - Lan, I. A.

AU - Chan, S. P.

AU - Chang, Shyy-Woei

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Two pairs of detailed Nusselt number (Nu) distributions on leading (LE) and trailing (TE) endwalls together with the Fanning friction factors (f) of a rotating two-pass parallelogram channel enhanced by the detached transverse ribs are simultaneously measured under forward and backward rotations. The tested Reynolds number, rotating number, density ratio, and buoyancy number are respectively in the ranges of 5,000<Re<15,000, 0<Ro<0.3, 0.044<Δρ/ρ<0.2, and 0<Bu<0.142. Due to the accelerating flows through the gaps between the detached ribs and channel endwalls, the transverse high Nu stripe emerges along the projection area of each detached rib on both static and rotating smooth endwalls. The disparities in the relative directions between Coriolis forces and channel periphery that restrains Coriolis flows at forward and backward rotations cause different heat transfer properties on the two pairs of rotating LE and TE. The area-averaged leading and trailing Nusselt numbers at forward rotations are 0.69-1.77 and 0.85-1.98 relative to the static-channel Nusselt number references (Nu0) respectively. With backward rotations, the ratios of regionally averaged Nusselt numbers between rotating and static channels for leading and trailing walls fall in the respective change to 0.86-2 and 0.91-1.76. At both forward and backward rotations, all the f factors over LE and TE are elevated from the static-channel levels (f0) and increased by increasing Ro. Channel averaged f/f0 ratios are respectively raised to 1.21-2.21 and 1.21-2.1 at forward and backward rotations. As the heat transfer enhancements attributed to the presence of detached transverse ribs taking precedence of the accompanying f augmentations, all the thermal performance factors (TPF) are above unity in the range of 1.26-2.94. Relative to the similar rotating two-pass parallelogram channel with attached 900 ribs, the detached ribs generate the higher degrees of heat transfer enhancements with the larger extents of f augmentations.

AB - Two pairs of detailed Nusselt number (Nu) distributions on leading (LE) and trailing (TE) endwalls together with the Fanning friction factors (f) of a rotating two-pass parallelogram channel enhanced by the detached transverse ribs are simultaneously measured under forward and backward rotations. The tested Reynolds number, rotating number, density ratio, and buoyancy number are respectively in the ranges of 5,000<Re<15,000, 0<Ro<0.3, 0.044<Δρ/ρ<0.2, and 0<Bu<0.142. Due to the accelerating flows through the gaps between the detached ribs and channel endwalls, the transverse high Nu stripe emerges along the projection area of each detached rib on both static and rotating smooth endwalls. The disparities in the relative directions between Coriolis forces and channel periphery that restrains Coriolis flows at forward and backward rotations cause different heat transfer properties on the two pairs of rotating LE and TE. The area-averaged leading and trailing Nusselt numbers at forward rotations are 0.69-1.77 and 0.85-1.98 relative to the static-channel Nusselt number references (Nu0) respectively. With backward rotations, the ratios of regionally averaged Nusselt numbers between rotating and static channels for leading and trailing walls fall in the respective change to 0.86-2 and 0.91-1.76. At both forward and backward rotations, all the f factors over LE and TE are elevated from the static-channel levels (f0) and increased by increasing Ro. Channel averaged f/f0 ratios are respectively raised to 1.21-2.21 and 1.21-2.1 at forward and backward rotations. As the heat transfer enhancements attributed to the presence of detached transverse ribs taking precedence of the accompanying f augmentations, all the thermal performance factors (TPF) are above unity in the range of 1.26-2.94. Relative to the similar rotating two-pass parallelogram channel with attached 900 ribs, the detached ribs generate the higher degrees of heat transfer enhancements with the larger extents of f augmentations.

UR - http://www.scopus.com/inward/record.url?scp=85054086450&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85054086450&partnerID=8YFLogxK

U2 - 10.1115/GT2018-75278

DO - 10.1115/GT2018-75278

M3 - Conference contribution

AN - SCOPUS:85054086450

SN - 9780791851081

VL - 5A-2018

BT - Heat Transfer

PB - American Society of Mechanical Engineers (ASME)

ER -