Buoyancy Driven Natural Ventilation through Horizontal Openings

Per Heiselberg, Zhigang Li

Research output: Contribution to journalJournal articleResearchpeer-review

9 Citations (Scopus)

Abstract

An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed.
Original languageEnglish
JournalInternational Journal of Ventilation
Volume8
Issue number3
Pages (from-to)219-231
ISSN1473-3315
Publication statusPublished - 2009

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Buoyancy
Ventilation
Froude number
Smoke
Visualization
Air
Gases
Temperature

Keywords

  • Natural ventilation
  • Airflow rate
  • Buoyancy
  • Horizontal opening
  • Tracer gas
  • LES

Cite this

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title = "Buoyancy Driven Natural Ventilation through Horizontal Openings",
abstract = "An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed.",
keywords = "Natural ventilation, Airflow rate, Buoyancy, Horizontal opening, Tracer gas, LES",
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language = "English",
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Buoyancy Driven Natural Ventilation through Horizontal Openings. / Heiselberg, Per; Li, Zhigang.

In: International Journal of Ventilation, Vol. 8, No. 3, 2009, p. 219-231.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Buoyancy Driven Natural Ventilation through Horizontal Openings

AU - Heiselberg, Per

AU - Li, Zhigang

PY - 2009

Y1 - 2009

N2 - An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed.

AB - An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit quite well with the Epstein's formula but in other cases the measured data show clear deviations from the Epstein's formula. Thus, revised formulas for natural ventilation are proposed.

KW - Natural ventilation

KW - Airflow rate

KW - Buoyancy

KW - Horizontal opening

KW - Tracer gas

KW - LES

M3 - Journal article

VL - 8

SP - 219

EP - 231

JO - International Journal of Ventilation

JF - International Journal of Ventilation

SN - 1473-3315

IS - 3

ER -