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长通道型结构内发生火灾时,由于通道侧壁的限制,烟气将很快运动至充分发展阶段,表现为沿通道轴向的一维水平蔓延。该文分析了一维水平蔓延阶段中上部热烟气层和下部冷空气层在分界面处的水平相对剪切运动,以及由此导致的烟气层质量流率的沿程增加。通过联立烟气作一维水平蔓延时的运动速度衰减规律,推导出了长通道型结构内烟气一维水平蔓延过程中的质量卷吸系数关系式。在模拟尺寸长通道实验台中进行了一系列实验,测得到了关系式中的未知参数,包括环境空气温度、一维水平蔓延阶段中两参考截面处的烟气流速、温度和烟气层厚度等,求出了一维水平卷吸系数。
When a fire occurs in a long-channel structure, the flue gas will quickly move to a full development stage due to the restriction of the side walls of the channel, manifesting as a one-dimensional horizontal spread along the channel axis. This paper analyzes the horizontal relative shear motion at the interface between the upper hot flue gas layer and the lower cold air layer in the one-dimensional horizontal spreading phase and the consequent increase of the mass flow rate along the flue gas layer. Through the law of motion velocity decay when the parallel flue gas is one-dimensional horizontal spread, the relationship between the mass entrainment coefficient of flue gas in the long-channel structure is derived. A series of experiments were carried out on a bench scale with long channels of simulated size. The unknown parameters in the relation were measured, including the ambient air temperature, the flue gas flow rate, the temperature and the thickness of the flue gas at the two reference cross sections in the one-dimensional horizontal propagation stage , Obtained a one-dimensional horizontal coiling coefficient.