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Experimental prediction on the performance and propagation of ceiling jets under the influence of wall confinement
- Gao, Zihe, Wan, Huaxian, Ji, Jie, Bi, Yubo
- Energy 2019 v.178 pp. 378-385
- emissions, energy, heat transfer, open space, pollutants, prediction, temperature, toxicity
- Characteristics of ceiling jets propagation are very significant for energy detecting and controlling once an undesirable energy source releasing flame and toxic pollutant emissions is erupted in a building. In many cases, the impinging ceiling jet flame will be affected by the nearby wall, especially for the energy source very close to or immediately against a wall. Four sets of experiments were conducted with energy source in open space, confined by an unbounded ceiling, confined by a wall-ceiling configuration and confined by two parallel walls (a corridor-like structure). Results show that the impinging ceiling jet-flame behaves very differently in different wall-ceiling configurations, the ceiling flame extension and the heat flux to nearby field increases dramatically with increasing confinement strength, from unbounded ceiling to narrow confined corridor-like structure. Based on the limits of flame extension, the temperature distribution under the ceiling can be divided into the near-field region within the ceiling flame and the far-field region beyond the ceiling flame. Predictive correlations of ceiling flame and temperature distribution are proposed to account for different wall-ceiling configurations. The results of this study have implications to optimize the design and arrangement of the ceiling-mounted heat and energy detection, protection and controlling systems.