基于图像亮度统计分析火焰高度特征

Flame Height Characteristics Based on Image Luminance

火焰高度是燃烧火焰的一个重要参数,它影响火焰的传播及辐射特性,而火焰高度特征包括平均火焰高度和脉动频率两个方面.基于Matlab视频图像分析,提出了通过统计火焰图像时间序列中各位置处出现亮点的概率和火焰中心线上的亮点个数,来提取火焰的平均高度和脉动频率的方法.开展了0.5 m×0.5 m、0.7 m×0.7 m和0.8 m×0.8 m三组方形油盘火试验,利用该方法获得了它们的平均火焰高度和脉动频率,并和Heskestad模型、Pagni模型、Bejan模型和Cetegen模型的理论预测值进行了对比,结果表明,该方法得出的平均火焰高度和火焰脉动频率均与理论预测值比较接近.

Flame height is a key parameter of a burning fire, which has great effect on radiation intensity and tire spread. The characteristics of flame height considered here include average flame height and flame oscillation frequency. Based on the video image processing technology provided by Matlab software, a new way to get average flame height and oscillation frequency was developed through calculating the occurrence probability of light points in different positions of sequence images and the number of light points on the centerline of burner. Experiments were conducted with the squares burner of 0. 5 m ×0. 5 m, 0. 7 m×0. 7 m, and 0. 8 m×0. 8 m respectively. The average flame height and flame oscillation frequency of these pool fires were determined by the new method, which agreed well with the theoretically predicted values by Heskestad model, Pagni model, Bejan model and Cetegen model.