撞击气化火焰边缘的分形特性

Fractal Characteristics of an Impinging Gasification-flame Edge

气化炉是IGCC发电系统的关键设备,在试验中采用火焰摄像系统拍摄了多喷嘴对置气化炉内撞击气化火焰图像,用像素点覆盖法计算了撞击气化火焰边缘的分形维数,提供了一种有效判断撞击气化火焰燃烧状态的方法。试验结果表明,撞击气化火焰边缘曲线具有分形特征。撞击火焰的边缘分形维数在点火阶段逐渐降低;从两喷嘴撞击向四喷嘴撞击过渡时火焰边缘曲线分形维数逐渐增大;随着操作负荷的增大,分形维数增大,但两喷嘴和四喷嘴撞击火焰之间的分形维数相差逐渐减小。

A gasification furnace is a key equipment item in an IGCC(integrated gasification combined cycle) power generation system.During tests,the authors have by using a flame camera system taken the pictures of impinging gasification-flames in a multi-nozzle and opposed gasification furnace.The fractal dimension of the impinging gasification-flame edge was calculated by using a pixel-covering method,providing an effective method for judging the combustion condition of the impinging gasification-flame.The test results show that the curves of the above-mentioned flame edge assume fractal characteristics.The fractal dimensions of the flame edge curve will gradually decrease during the ignition stage but increase during the process of transition from a two-nozzle impinging to a four-nozzle one.With an increase in the operational load,the fractal dimension will also increase.However,the difference between the fractal dimension of a two-nozzle and four-nozzle impinging flames will gradually diminish.