通过高速摄像仪获取加速度3． 6、5． 4、6． 5m/s2 下的直线移动火源扩散火焰匀加速图像序列，经图像处理得到不同投影灰度的火焰图像结构图，再利用分形理论研究了其投影灰度下的分形特征． 结果表明: 速度和加速度的作用产生的切向作用力与燃烧产生的浮力的共同作用，会改变移动火焰的分形，比静止火焰更加复杂; 不同投影灰度的分形维数在燃烧控制区随速度增大而增大，在过渡区随速度增大而减小，在横掠风控制区随速度变化趋于平稳; 不同投影灰度的分形维数达到最大值和最小值对应的速度差别较大且加速度大时达到最大分形维数的时间短，火焰图像投影灰度的分形维数随灰度增加而减小，但在加速度和速度较大时影响减弱．

The image series of the diffusion flames of the moving fire in linear motion at the speeds of 3. 6,5. 4 and 6. 5m/s2 were acquired by using a high-speed video camera,and the structure charts of the flame images of different projected grayscales were acquired through the image processing.Then,the fractal structure characteristic of the projected grayscale was investigated.The results show that ( 1) the fractal dimension of the diffusion flame of the moving fire can be changed by the combined effects of both the buoyancy generated by combustion and the tangential force generated by the flame speed and its acceleration,and the structure of moving flames is complicated than that of static flames; ( 2) as the flame speed increases,the fractal dimension of the diffusion flames of different projected grayscales will increase in the combustion control zone,but decrease in the transition zone and fluctuate within a small range in the cross flow control zone; ( 3) the speeds of moving fire,at which the fractal dimension of the flame images of different projected grayscales reaches the maximum and the minimum,are greatly different,and the time to reach the maximum fractal dimension is shorter; and ( 4) the fractal dimension of the flame images projected grayscale decrease with the increase of grayscale,but the decrease is weakened when the acceleration and speed of the moving fire are higher.