有风条件下室内火灾自然排烟模型试验研究

Experimental Study on Natural Ventilation under Surrounding Winds with a Reduced-scale Model

采用缩尺度试验方法对有风条件下室内火灾自然排烟过程准稳态进行研究,分析不同补气口、排烟口位置和风向对排烟效果的影响。试验结果表明:将补气口设在迎风面,排烟口设在背风面或侧风面时将获得比没有环境风时更好的自然排烟效果;而在其他情况下,环境风将通过减小排烟口处内外压差以及对室内烟气层产生扰动来降低自然排烟效果。在设置建筑自然排烟系统时,应综合考虑火灾具体情况以及当地风速条件,选择对自然排烟有利的排烟口与补气口位置组合,以提高自然排烟的效果。

Experimental study on quasi-steady state of natural ventilation under surrounding winds was performed using a reduced-scale model. Contributions of vents and wind direction were discussed. It is demonstrated that wind will enhance the performances of natural ventilation when the air inlet is windward and the exhaust outlet is leeward or on the crosswind side of the building. On other cases, wind will decrease the performances of natural ventilation by reducing pressure difference through exhaust vent and disturbing smoke layer in the building. When designing a natural smoke exhaust system, combination of air inlet and exhaust vent should be carefully considered not to decrease the performances of natural ventilation according to the configuration of building and local meteorological conditions.