In order to find the influence on plume rise subjected to stack effect and buoyancy in shaft fires, a small-scaled fire shaft bench was established and experiments were conducted to measure temperature in two-end-open shaft and bottom-end-closed shaft under different kinds of fuels and different fire pool sizes, and driving forces of upward hot smoke were analyzed. It turned out that hot smoke was subjected to the action of both stack effect and buoyancy in two-end-open shaft, and stack effect would play a leading role; hot smoke was only subjected to its own buoyancy in bottom-end-closed shaft. By comparison, the driving force of upward hot smoke in two-end-open shaft was stronger than that in bottom-end-closed shaft. The ratio between the driving force of upward smoke in two-end-open shaft and bottom-end-closed shaft grows with increasing fire diameters under the same fire and shaft dimensions, and the slope equals to 0. 32.%为得到竖井内烟囱效应与浮力对羽流上升造成的影响,搭建了小尺寸竖井火灾实验平台,测量了不同燃料、不同油池尺寸条件下两端开放及底部封闭竖井内温度分布,对各驱动力进行了理论分析.结果表明:两端开放竖井内火灾热烟气上升受到烟囱效应与自身浮力的共同作用,且烟囱效应驱动力占主导；底部封闭竖井内热烟气上升仅靠自身浮力作用；两端开放竖井内烟气受到向上的驱动力更大.在相同火源及竖井尺寸条件下,两端开放竖井内向上驱动力与底部封闭竖井内向上驱动力的比值随油池直径的变大而增大,平均斜率为0.32.
展开▼
