水煤浆烧嘴头部混合流动及压差波动数值仿真模拟

Numerical simulation of mixed flow and differential pressure fluctuation of coal water slurry burner head

针对水煤浆烧嘴运行中的压差波动问题,采用FLUENT软件从物性参数及烧嘴结构等方面进行了仿真模拟。分析了水煤浆烧嘴在不同黏度和结构下的头部混合流动,得到了组分、压力、速度分布云图,监测了煤浆入口压力波动频率和振幅。总结了水煤浆烧嘴的雾化过程,分析了黏度、结构对烧嘴压差波动的影响规律。由仿真模拟结果可知:随着煤浆黏度降低,预混式烧嘴的雾化效果变得更好,但是喷出速度波动变大;相同煤浆黏度下,预膜式烧嘴的煤浆入口压力平均振幅为预混式烧嘴的57%,更有利于保持烧嘴压差稳定。

Aiming at the problem of differential pressure fluctuation of coal water slurry(CWS)burner in operation,FLUENT was used to simulate the physical parameters and burner structure.The head mixed flow of CWS burner at different viscosity and structure was analyzed,the distribution nephogram of composition,pressure and velocity was obtained,and the fluctuation frequency and amplitude of coal slurry inlet pressure were monitored.The atomization process of CWS burner was summarized,the influence rule of viscosity and structure on the differential pressure fluctuation of the burner was analyzed.The simulation results showed that:with the decrease of coal slurry viscosity,the premixed structure had better atomization effect,but with larger fluctuation of spray velocity;at the same coal slurry viscosity,the average amplitude of coal slurry inlet pressure of the prefilming burner was 57%that of the premixed burner,more conducible to keeping the stable burner differential pressure.