火灾情况下侧向连续开口楼梯井中性面位置

Neutral-plane location in stairs with continuous side opening in a fire

通过1/3缩尺寸实验和模拟研究楼梯井侧向连续开口时中性面位置。研究表明,此种开口形式下,整体楼梯井不存在单一中性面,中间紊乱楼层存在各自小中性面,楼梯井与外部通过侧面开口形成若干个竖井小循环;随着火源功率的增加,紊乱楼层数增加,小循环数也增加;随着火源位置的提高,楼梯井下部空气流入的范围扩大,紊乱楼层数减小,小循环数也减小。楼梯井中部温度并不是随着高度逐步降低,在中部紊乱楼层中出现下部温度低于顶部温度的现象。

Experiments in a 1/3 model of a stairwell and simulations were carried out in order to investigate the neutral-plane location under a side continuous opening in stairwell. The fol- lowing conclusions were obtained： The neutral-plane does not exist for overall stairwell, and small neutral surface exists for disordered floors in stairwell separately. And a number of shaft small cycles were formed between in and out the stairwell by the side opening. With the increasing of fire power, the number of disordered floors increased, the number of small cycles also increased. With the location of fire raised, the range of air flow into the stairwell increased, the number of disordered floors de- creased, the number of small cycles also decreased.