### Abstract

Experiments are performed to investigate the local heat/mass transfer characteristics for flow through a single circular hole in a thin perforated plate (modeling a combustor wall). The naphthalene sublimation technique is employed to determine the local values on the hole's inner surface and in the vicinity of the hole entrance and exit. The hole-length-to-diameter ratio varies from 0.5 to 1.5, and the ratio of the diameter of the outer boundary (active area) to the hole diameter varies from 1.5 to 4.5. The Reynolds number based on the hole diameter is between 600 and 30 000. On the windward surface, the heat/mass transfer coefficient increases rapidly as the flow approaches the hole entrance due to flow acceleration with a thin boundary layer. Inside the hole, a separation zone at the hole entrance decreases with increasing Reynolds number and then remains constant, approximately 0.56 hole diameter in depth, as the Reynolds number is increased further. The mass transfer coefficient at the reattachment point is about four times that for fully-developed tube flow. The mass transfer variations indicate a laminar separation and a turbulent reattachment flow in this Reynolds number range. The transfer coefficient on the leeward surface is small for the single hole flow because of a weak entrainment-flow velocity. The overall transfer rate is dominated by the inside hole surface (approximately 60%) in spite of its small surface area. Correlations are proposed for local/average heat transfer in short single holes as a function of Reynolds numbers and hole aspect ratios.

Original language | English |
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Pages (from-to) | 2431-2443 |

Number of pages | 13 |

Journal | International Journal of Heat and Mass Transfer |

Volume | 40 |

Issue number | 10 |

DOIs | |

Publication status | Published - 1997 Jan 1 |

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### All Science Journal Classification (ASJC) codes

- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes

### Cite this

*International Journal of Heat and Mass Transfer*,

*40*(10), 2431-2443. https://doi.org/10.1016/S0017-9310(96)00270-0

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*International Journal of Heat and Mass Transfer*, vol. 40, no. 10, pp. 2431-2443. https://doi.org/10.1016/S0017-9310(96)00270-0

**Experimental mass (heat) transfer in and near a circular hole in a flat plate.** / Cho, Hyung Hee; Jabbari, M. Y.; Goldstein, R. J.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Experimental mass (heat) transfer in and near a circular hole in a flat plate

AU - Cho, Hyung Hee

AU - Jabbari, M. Y.

AU - Goldstein, R. J.

PY - 1997/1/1

Y1 - 1997/1/1

N2 - Experiments are performed to investigate the local heat/mass transfer characteristics for flow through a single circular hole in a thin perforated plate (modeling a combustor wall). The naphthalene sublimation technique is employed to determine the local values on the hole's inner surface and in the vicinity of the hole entrance and exit. The hole-length-to-diameter ratio varies from 0.5 to 1.5, and the ratio of the diameter of the outer boundary (active area) to the hole diameter varies from 1.5 to 4.5. The Reynolds number based on the hole diameter is between 600 and 30 000. On the windward surface, the heat/mass transfer coefficient increases rapidly as the flow approaches the hole entrance due to flow acceleration with a thin boundary layer. Inside the hole, a separation zone at the hole entrance decreases with increasing Reynolds number and then remains constant, approximately 0.56 hole diameter in depth, as the Reynolds number is increased further. The mass transfer coefficient at the reattachment point is about four times that for fully-developed tube flow. The mass transfer variations indicate a laminar separation and a turbulent reattachment flow in this Reynolds number range. The transfer coefficient on the leeward surface is small for the single hole flow because of a weak entrainment-flow velocity. The overall transfer rate is dominated by the inside hole surface (approximately 60%) in spite of its small surface area. Correlations are proposed for local/average heat transfer in short single holes as a function of Reynolds numbers and hole aspect ratios.

AB - Experiments are performed to investigate the local heat/mass transfer characteristics for flow through a single circular hole in a thin perforated plate (modeling a combustor wall). The naphthalene sublimation technique is employed to determine the local values on the hole's inner surface and in the vicinity of the hole entrance and exit. The hole-length-to-diameter ratio varies from 0.5 to 1.5, and the ratio of the diameter of the outer boundary (active area) to the hole diameter varies from 1.5 to 4.5. The Reynolds number based on the hole diameter is between 600 and 30 000. On the windward surface, the heat/mass transfer coefficient increases rapidly as the flow approaches the hole entrance due to flow acceleration with a thin boundary layer. Inside the hole, a separation zone at the hole entrance decreases with increasing Reynolds number and then remains constant, approximately 0.56 hole diameter in depth, as the Reynolds number is increased further. The mass transfer coefficient at the reattachment point is about four times that for fully-developed tube flow. The mass transfer variations indicate a laminar separation and a turbulent reattachment flow in this Reynolds number range. The transfer coefficient on the leeward surface is small for the single hole flow because of a weak entrainment-flow velocity. The overall transfer rate is dominated by the inside hole surface (approximately 60%) in spite of its small surface area. Correlations are proposed for local/average heat transfer in short single holes as a function of Reynolds numbers and hole aspect ratios.

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U2 - 10.1016/S0017-9310(96)00270-0

DO - 10.1016/S0017-9310(96)00270-0

M3 - Article

VL - 40

SP - 2431

EP - 2443

JO - International Journal of Heat and Mass Transfer

JF - International Journal of Heat and Mass Transfer

SN - 0017-9310

IS - 10

ER -