低NO_x旋流煤粉燃烧器气固两相流模拟

Numerical Simulation of Gas-particle Two Phase Flow Field for the Low NO_x Swirl Burner

为提高旋流煤粉燃烧器稳燃与燃尽性能,降低NOx排放。通过数值模拟方法研究了在中心风速4~9 m/s,内二次风速5~16 m/s,外二次风速8~20 m/s,外二次风叶片角度30°~75°时,DBC-OPCC型低NOx旋流燃烧器射流的气固两相流流动特性。结果表明:两侧回流区随着内二次风速增加而向中心靠拢,其长度随着中心风速的增加而缩短。内、外二次风在一定程度上影响一次风的刚度以及回流区的范围和方向。外二次风叶片开度,与相邻两叶片之间中心区域的径向速度和出口流场轴向速度之间存在一定规律。

In order to improve burnout rate and the stable combustion performance of swirl burner and reduce NOx emission numerically simulation(by fluent)was used to investigate the gas-solid two-phase flow characteristics of the DBC-OPCC type low NOx swirl burner in the parameters range of the central wind speed 4~9 m/s,internal secondary air speed 5~16 m/s,external secondary air speed 8~20 m/s and the angle 30°~75°of the outer secondary wind blade.The results show that:internal secondary air speed increases,the distance between the two sides of the recirculation zone toward the center.The length of the recirculation zone shortens with the increase of the central wind speed.The internal secondary air and external secondary air influence the stiffness of the primary air.The external secondary air speed affects the range and direction of the recirculation zone.The external secondary air blade opening affects the radial velocity and the axial velocity of the outlet flow field in the central region of the two blades.