Abstract
The transient natural displacement ventilation driven by a localized heat source at the floor of a room is examined to understand the airflow behavior and the relevant thermal stratification characteristic. Two modified theoretical models are developed on the basis of classical plume theory and Kaye and Hunt’s model. The buoyant layer is modeled as composed of a near-ceiling layer and a warm layer rather than being well-mixed. Some assumptions on the buoyancies of the near-ceiling layer and the outflow through the upper opening are made in the two modified models for simplicity. Comparisons are made between the predictions of Kaye and Hunt’s model and the two modified models and experimental data reported in the literature. Two modified models are shown to perform better than Kaye and Hunt’s model. Meanwhile, the predictions of the modified model I seem to agree slightly better with the experimental data than those of the modified model II. Typically, the average relative deviation between the three models’ predictions of the lowest interface height and the experimental data are about 4.2% (modified model I), 4.6% (modified model II), and 4.9% (Kaye and Hunt’s model).
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References
Andersen KT (1995). Theoretical considerations on natural ventilation by thermal buoyancy. ASHRAE Transactions, 101(2): 1103–1117.
Bolster D, Maillard A, Linden P (2008). The response of natural displacement ventilation to time-varying heat sources. Energy and Buildings, 40: 2099–2110.
Bower DJ, Caulfield CP, Fitzgerald S D, Woods AW (2008). Transient ventilation dynamics following a change in strength of a point source of heat. Journal of Fluid Mechanics, 614: 15–37.
Chen ZD, Li Y (2002). Buoyancy-driven displacement natural ventilation in a single-zone building with three-level openings. Building and Environment, 37: 295–303.
Cooper P, Hunt GR (2010). The ventilated filling box containing a vertically distributed source of buoyancy. Journal of Fluid Mechanics, 646: 39–58.
Fitzgerald SD, Woods AW (2007). Transient natural ventilation of a room with a distributed heat source. Journal of Fluid Mechanics, 591: 21–42.
Fitzgerald SD, Woods AW (2010). Transient natural ventilation of a space with localised heating. Building and Environment, 45: 2778–2789.
Flynn MR, Caulfield CP (2006). Natural ventilation in interconnected chambers. Journal of Fluid Mechanics, 564: 139–158.
Germeles AE (1975). Forced plumes and mixing of liquids in tanks. Journal of Fluid Mechanics, 71: 601–623.
Hunt GR, Cooper P, Linden PF (2001). Thermal stratification produced by plumes and jets in enclosed spaces. Building and Environment, 36: 871–882.
Hunt GR, Kaye NB (2006). Pollutant flushing with natural displacement ventilation. Building and Environment, 41: 1190–1197.
Kaye NB, Hunt GR (2004). Time-dependent flows in an emptying filling box. Journal of Fluid Mechanics, 520: 135–156.
Kaye NB, Hunt GR (2007). Heat source modeling and natural ventilation efficiency. Building and Environment, 42: 1624–1631.
Kaye NB, Hunt GR (2010). The effect of floor heat source area on the induced airflow in a room. Building and Environment, 45: 839–847.
Li Y (2000). Buoyancy-driven natural ventilation in a thermally stratified one-zone building. Building and Environment, 35: 207–214.
Linden PF, Kaye NB (2006). Interacting turbulent plumes in a naturally ventilated enclosure. International Journal of Ventilation, 4: 301–310.
Linden PF, Lane-Serff GF, Smeed DA (1990). Emptying filling boxes: The fluid mechanics of natural ventilation. Journal of Fluid Mechanics, 212: 309–335.
Sandbach SD, Lane-Serff GF (2011). Transient buoyancy-driven ventilation: Part 1. Modelling advection. Building and Environment, 46: 1578–1588.
Stoakes P, Passe U, Battaglia F (2011). Predicting natural ventilation flows in whole buildings. Part 1: The Viipuri Library. Building Simulation, 4: 263–276.
Turner JS (1986). Turbulent entrainment: The development of the entrainment assumption and its application to geophysical flows. Journal of Fluid Mechanics, 173: 431–471.
Yang X, Wang G, Zhong K, Kang Y (2012). Transient pollutant flushing of buoyancy-driven natural ventilation. Building Simulation, 5: 147–155.
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Yang, X., Kang, Y. & Zhong, K. Theoretical predictions of transient natural displacement ventilation. Build. Simul. 6, 165–171 (2013). https://doi.org/10.1007/s12273-013-0098-7
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DOI: https://doi.org/10.1007/s12273-013-0098-7