电站煤粉锅炉炉内压力信号的混沌特性

大型电站燃煤锅炉炉内过程是一个复杂的非线性时变过程.综合考虑了电站煤粉锅炉实际运行和混沌动力学理论应用,研究了以炉内压力为参变量的炉内混沌运动特性.利用功率谱方法、Cao方法以及Kolmogorov熵,可确认炉内压力信号为包含着随机信号的混沌信号,并且随机信号的波动幅度约为混沌信号波动幅度的50%～75%.在某煤粉锅炉正常运行状态下以延时8 s、嵌入维数8重构炉内混沌运动的相空间,计算得到炉内运动关联维为6.56,存在正的lyapunov指数0.019 4,Kolmogorov熵为0.297 bits/s.最后指出,在实际锅炉运行中,可利用各混沌特征指数对炉内系统的深入分析,进一步指导电站锅炉优化运行操作.

Chaotic Characteristics of In-furnace Pressure Signals in a Pulverized Coal-fired Utility Boiler

The in-furnace process of a large-sized coal-fired utility boiler features a complex non-linear time-variation one.With a comprehensive consideration of the practical operation of a coal-fired utility boiler and the application of chaotic kinetics theory,studied were the in-furnace chaotic motion characteristics with the in-furnace pressure serving as a parameter-variable.By employing a power spectrum method,Cao method and Kolmogorov entropy,it can be confirmed that the in-furnace pressure signals are chaotic ones involving random signals,of which the fluctuation range is about 50% to 75% of that of the chaotic signals.If the phase space for chaotic motion is restructured by a time delay of 8 s and the number of inserted dimensions totaling 8 in a pulverized-coal boiler under a normal operating condition,the correlative in-furnace motion dimension is ascertained as 6.56 through a calculation and there exists a positive Lyapunov index of 0.019 4 with Kolmogorov entropy being 0.297 bits/s.Finally,it should be noted that during a practical boiler operation,various indexes featuring chaotic characteristics can be used to further depict an in-furnace system,thus offering further guidance for the optimized operation of a utility boiler.