扩口位置对旋流燃烧器出口流场影响的研究

Effects of Outlet Positions on Characteristics of Gas-particle Two Phase Flows of the Swirl Burner

通过采用三维相位多普勒颗粒分析仪对中心给粉旋流煤粉燃烧器不同一次风扩口位置下的气固两相流动特性进行了测量。在2种扩口位置下,从燃烧器出口至x/d=0.5截面气、固两相轴向速度分布均呈双峰结构;在中心线处,气相轴向速度明显滞后于固相轴向速度,实际扩口燃烧器的气相、固相的轴向速度衰减速度快,且在x/d=1.5的截面开始,出现颗粒穿越部分回流区。在x/d=0.3截面,气、固两相切向速度分布是典型的Rankine涡结构;在燃烧器出口至x/d=0.7截面,气、固两相径向速度分布呈双峰结构。中心给粉燃烧器在燃烧器中心形成较高的颗粒浓度分布。

A throe-component particle-dynamics anemometer was used to measure, in the near-burner region, the characteristics of gas-particle two phase flows with the central-fuel-rich swirl coal combustion （CSCC） burner under two different positions of primary air outlet, on a gas-particle test facility. In the two different positions, from the burner jet to x/d=0.5, profiles of axial mean velocities for air and particles have two crest zones; in the centerline, air axial mean velocities falls evidently behind particle axial mean velocities, axial mean velocities for air and particles with the actual position reduce faster and particles penetrate some central recirculation zone（CRZ） beginning from x/d=1.5 cross section. In the x/d= 0.3 cross section, profiles of tangential mean velocities for air and particles is the typical Rankine eddy configuration; from the burner jet to x/d=0.7 cross section, profiles of radial mean velocities for air and particles have two crest zones. In the center of the burner ,there is a high particle relative volume fraction.