Buoyancy-Driven Exchange Flow Through Small Openings in Horizontal Partitions

Epstein, Michael

doi:10.1115/1.3250589

Cited by 132 publications

(113 citation statements)

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“…Transitions between bid irectional and unidirectional flows, of the kind included in the studies of Epste in et a L, [2,3] and the issue of concern in connection with ceiling apertures, are extremely complex and no theory is attempted for this case.…”

Section: Ceiling Aperturesmentioning

confidence: 99%

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Inflow Of Air Required At Wall And Ceiling Apertures To Prevent Escape Of Fire Smoke

Heskestad¹,

Spaulding²

1991

Fire Safety Science - Proceedings of the Third International Sy

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Expe r iments have been conducted to determine cr I tical Froude numbers associated with required inflow of air to a fire space through wall and ceil ing apertures to prevent escape of smoke.The exper iments were conducted mostly on reduced, model scale, with verification in a 2.4 m high test room.Critical Froude numbers, as formulated, were insensitive to aperture geometry.Those for wall apertures varied slowly and predictably with the vertical temperature distribution in the room, consistent with a discharge coefficient of 0.64 for the inflow. Those for ceiling apertures exhibited a dependence on an aperture Grashof number, with both a highGrashof number asymptote and an apparent low-Grashof number asymptote. While discharge coefficients for wall apertures can be considered constant near 0.64 for aperture Froude numbers larger than cr itical, the discharge coefficient for ceiling apertures increased from 0.19 near the critical Froude number, toward the familiar isothermal value for sharp-edged orifices of 0.61 near a Froude number seven times larger than the critical.

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Section: Ceiling Aperturesmentioning

confidence: 99%

“…Epstein [2], and Epstein and Kenton [3], have studied the combined natural and forced flows through openings in horizontal partitions using a heavier liquid, brine, on top of the partition and a lighter liquid, fresh water, below the parti t i on .…”

Section: Introductionmentioning

confidence: 99%

Inflow Of Air Required At Wall And Ceiling Apertures To Prevent Escape Of Fire Smoke

Heskestad¹,

Spaulding²

1991

Fire Safety Science - Proceedings of the Third International Sy

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“…Only Epstein( 1988) and Epstein and Kenton( 1989) extended the work from a single opening to multiple openings. They observed three different flow configurations involving both one-way and countercurrent flows within the openings.…”

Section: Studies On Flow Patternsmentioning

confidence: 99%

“…11, for L/D= 0.0313 Rayleigh-Taylor type instability was observed in each hole. This flow pattern is called as oscillatory exchange flow, a flow regime analyzed by M. Epstein (1988) and T.A.Conover, R.Kumar, and J.S. Kapat (1995).…”

Section: Fig 11mentioning

confidence: 99%

Mixing processes in high-level waste tanks. Progress report, September 15, 1996--September 14, 1997

Peterson¹

1997

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“…Epstein [5] studied the exchange flow of water and brine through various vertical tubes, experimentally and theoretically. Mercer et al [6] experimentally studied an exchange flow through inclined tubes with water and brine.…”

Section: Introductionmentioning

confidence: 99%

Study on the Experiments and the Numerical Analysis of Exchange Flow Behavior in the Unstably Stratified Field

Fumizawa

Saito²,

Uchiyama³

et al. 2015

IJEPE

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Abstract:In the flow mechanism of unstably stratified field, occurs after Rayleigh-Taylor instability. Buoyancy-driven exchange flows were investigated the helium-air flow in the vertical narrow pathway between upper air chamber and lower helium chamber. Exchange flows may occur following the opening of a window for ventilation, when fire breaks out in a room, as well as when a pipe ruptures in a high temperature gas-cooled nuclear reactor. The numerical analysis and experiment in this paper was carried out in a test chamber filled with helium and the flow was visualized using the smoke wire method. The flow behavior was recorded by a high-speed camera combined with a computer system. The image of the flow was transferred to digital data, and the flow velocity was measured by PTV and PIV software. The mass fraction in the test chamber was measured using electronic balance. The detected data was arranged by the densimetric Froude number of the exchange flow rate derived from the dimensional analysis. A method of mass increment was developed and applied to measure the exchange flow rate. As the result, it is revealed that three dimensional structure of counter current exchange flow in the narrow flow path such as rotation and circulation flows by the optical system, mass inclement method and numerical analysis of moving particle method as well as HSMAC method.

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Buoyancy-Driven Exchange Flow Through Small Openings in Horizontal Partitions

Cited by 132 publications

References 0 publications

Inflow Of Air Required At Wall And Ceiling Apertures To Prevent Escape Of Fire Smoke

Inflow Of Air Required At Wall And Ceiling Apertures To Prevent Escape Of Fire Smoke

Mixing processes in high-level waste tanks. Progress report, September 15, 1996--September 14, 1997

Study on the Experiments and the Numerical Analysis of Exchange Flow Behavior in the Unstably Stratified Field

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