新型双通道煤粉燃烧器流场模拟

Flow field simulation to new type two-channel pulverized coal burner

为了优化新型双通道煤粉燃烧器结构参数,采用计算流体动力学软件建立燃烧器-回转窑物理模型,使用κ-ε湍流模型和SIMPLE算法,对回转窑内流场进行冷态数值模拟。分析旋流角度和旋流风速变化对回流区的影响,结果表明:喷嘴附近二次风存在旋转现象;旋流风角度增大,回流区范围扩大,向靠近燃烧器方向移动,旋流风速增大,回流区范围增加幅度较小;低旋流角度,依赖轴向速度差卷吸二次风,高旋流角度加快旋流风径向扩散,不利于卷吸二次风。

In order to optimize the structural parameters ofthe new two-channel pulverized coal burners, physical modelof the burner-rotary kiln system is established usingcomputational fluid dynamics software, and then, the coldnumerical simulation to the flow field within kiln is studiedby means of k-e turbulence model and SIMPLE mathlanguage, and the influence of different angle and/or velocityof the swirling gas on the backflow area out of burner isanalyzed. The calculation results indicate that secondary airspinning is existed near the burner nozzle; backflow areaexpands and moves closer toward the burner when swirlingangle increases, but only small backflow area expansionoccurs when swirling gas speed increases. At low swirl flowangle, secondary air will be sucked because of the axialvelocity difference, while at high swirl flow angle, the radialdiffusion for swirling gas will be speeded up, which isunfavorable to suck the secondary air.