The Combustion Characteristics Extraction And Study Of Diffusion Flame Of Moving Fire In Linear Motion

With the development of transportation and widely used, and the speed and using frequency of transportation is constantly increasing, giving rise to the fire accident increasingly caused in use. This kind of fire, namely moving fire, will change its spatial location, because the fire is in a state of relative motion with the surrounding air. High speed of moving fire itself will cause the surrounding air turbulence, overlapping the turbulence moving fire, then lead to intensified combustion chemical reaction of moving fire, and make that the transient combustion characteristics of diffusion flame of moving fire becomes more complex.However, scholars at home and abroad who study the diffusion flame characteristics and mechanism of moving fire are still lack of exercise by far. Therefore, to carry out the diffusion flame characteristics and mechanism of moving fire are highly essential, and it is accurate assessment groundwork of this kind of fire development tendency. This paper studies have the practical engineering application value and theoretical significance to predict the fire occurs, at the same time, is helpful to enrich the theory of diffusion flame in a certain extent.Applying DRS gray high-speed camera, experimental system of linear motion moving fire, image processing technology and the fractal theory, fractal structure characteristic of the diffusion flame of moving fire was studied. The results revealed that the diffusion flame of moving fire possesses fractal dimension character and it increases with the velocity in the same acceleration. When the velocity of moving fire reaches a certain value, fractal dimension of the diffusion flame increases within small range. In the condition of large acceleration and velocity, fractal dimension of the diffusion flame increase rapidly with the velocity, and large acceleration and velocity can influence the wrinkle and distortion of the diffusion flame of moving fire. There are certain differences between moving fire and static fire, which can be identified by comparison of the fractal dimension of moving fire and static fire.Based on the experimental system of linear motion moving fire, the image series of the diffusion flame of moving fire on acceleration motion were acquired by using Motion the Corder Analyzer color high-speed camera, and its inclination characteristic was studied. The results show that flame inclination increasing has three stages changing velocity in non-inertial system. It is not in same direction between flame resultant and flame inclination. In non-inertial system, the flame resultant angle shifts first to the flame inclination and there is an angle between them. Moreover, the higher acceleration flame is, the more sluggish flame inclination will be. With the increase of flame speed, the air resistance increase and the angle decrease, they finally tend to 90°.Using modern color image processing technology extracted the image data of color flame region of the linear motion moving fire. Combining three-color thermometry, the variation of the flame temperature field affected by velocity and acceleration was studied. The results demonstrate that the average temperature and the maximum temperature in flame region have three stages changing velocity on the same acceleration. Similarities were found in variation with velocity of the average temperature and the maximum temperature in flame region.These studies are helpful to the diffusion flame of moving fire in linear motion.