液体燃料碳原子数对微尺度扩散火焰特性的影响

In order to get characteristics of the micro-scale diffusion flame of liquid fuels, n-pentane, n-heptane, n-octane, n-decane, n-dodecane were studied experimentally. The following results are obtained. (1) The diffusion flame shapes are different, including spherical shape, ellipsoidal shape, slender shape, agminated shape and explosive shape depending on the flow rate; the more carbon contained in the fuel, the smaller the combustion limit is. (2) The flame height is proportional to Reynolds number, and the fuel containing more carbon has smaller ratio of flame height and Reynolds number. Roper's model for estimating diffusion flame height applies to liquid alkane as well. The error between the experiment value and the model is within 25%. (3) The temperature of tube wall decreases as the flow rate increase, and the temperature of flame increases instead. The flame temperature depends on the shapes of these flame. The temperature of tube wall and flame temperature of different fuel decrease with the increase of carbon content.