有侧开缝的竖直通道内旋转火焰高度特性

为研究侧开缝竖直通道内旋转火焰高度的特性,搭建了内部尺寸为32cm(长)×32cm(宽)×200cm(高)的竖直通道,选取正庚烷和酒精为燃料,在斜对侧开缝和正对侧开缝两种形式下进行了不同直径火源的旋转火焰实验.实验结果表明,初期旋转火焰的高度值首先经历一个相对短暂的前期稳定阶段,之后达到最大值稳定阶段;以正庚烷为燃料形成的强烈旋转火焰高度在后期迅速下降,而以酒精为燃料时火焰高度的下降会经历一个缓冲的阶段;当以正庚烷为燃料时,火焰高度同时受到浮力和旋转强度的双重影响.并根据实验结果对火焰高度的无量纲表达式进行了修正.

Flame Height Characteristics of Fire Whirls in a Vertical Channel with Gaps

In order to study the height characteristics of fire whirls in a vertical channel, experiments of fire whirls induced by ethanol and N heptane in different diameter fuel pans were performed in a vertical channel with a dimension of 32 cm (length) ×32 cm (width) ×200 cm (height) and corner gaps, opposite gaps, respectively. In the experiments, the flame height reached its maximal stage after a relatively short primary stage. The later height of stronger fire whirls induced by N heptane dropped rapidly, but for ethanol, there existed a buffer stage. For stronger fire whirls induced by N-heptane, both buoyancy and violent rotating had an obvious effect on flame height. The dimensionless expression for flame height was revised based on the results of experiments.