烟囱效应形成机理的实验

依据相似原理建立小尺寸竖井实验台，研究了竖井底部温度和前室补气口流速随火源与竖井中心线距离的变化规律，建立了稳态条件下的竖井内温度、速度分布模型．研究结果表明，烟囱效应的产生主要是由于竖井内外压差与烟气自身浮力的联合作用，但是在不同范围内所发挥的作用不同：在火源距离竖井中心线较近区域（l／L〈0.825），竖井内外压差起主要作用；在火源距离竖井中心线较远区域（l／L〉0.825），烟气的自身浮力起主要作用．

Experimental study on the generation mechanism of stack effect

Based on the comparability theory,a scaling shaft model was established for studying how temperature on the bottom of shaft and the velocity on the opening of the fire room change with distance between fire source and the centerline of shaft,and a new steady model for the distribution of temperature and velocity was introduced.It is shown that the occurrence of stack effect is due to the combined buoyancy-and pressure-driven flow in a vertical shaft generally,but each force is dominant in some characteristic domain: pressure difference plays an important role where l/L<0.825,and when l/L>0.825,buoyancy is the most important factor.