火源位置对腔室火流动特性影响的实验研究

腔室火流动特性是影响腔室火灾蔓延与通风状况的重要因素。通过一系列小尺度腔室火实验,研究了火源位置变化对腔室火流动特性的影响。实验结果表明,随着火源沿腔室底部从壁面向开口方向移动,在开口中性面以上,同一高度处压差与流速增大,中性面高度和烟气层高度均降低,并导致开口质量流率增大。与火源强度相比,火源位置变化对烟气层高度的影响更为显著。火源位置对中性面高度及烟气层高度的影响在壁面处及开口处更为显著,腔室中部位置变化的影响相对较小。火源由壁面向开口移动,会造成火焰高度降低和水平伸长量增加。基于实验数据,给出了考虑耦合火源位置的腔室内火焰水平伸长量的表达式。研究结果可为相关场景下的腔室火灾理论模型提供实验结果支撑。

Experimental study on the effects of fire locations on the flow characteristics of compartment fires

Flow characteristics play important roles in the fire spread and ventilation condition of compartment fires. Aseries of reduced-scale experiments were carried out in this paper, in order to study the effects of fire locations on the flow characteristics of compartment fires. Experimental results indicate that, as the fire source moves from the wall to the opening, the pressure difference and velocity (at the same height above the neutral plane) increase, and both the neutral plane height and smoke layer height decrease, which result in the increase of the mass flow rate. As compared with the fire intensity, the fire location has more significant effects on the smoke layer height. The effects of the fire location on the neutral plane height and smoke layer height are more significant at the wall and the opening, as compared with that in the center. As fire source moves from the wall towards the opening, the flame height and the flame horizontal extent will respectively decrease and increase. Based on the experimental data, a new correlation is proposed to characterize the flame horizontal extent coupling with the effects of fire location. The results of this paper can provide experimental supports for the theoretical models under relevant compartment fire scenarios.