集流导叶对喷嘴射流刚性的影响

喷嘴射流刚度对电站锅炉炉内空气动力场影响较大,在喷嘴入口增加集流导叶使工质更加集中,提高射流刚度。利用数值方法,分析不同形状导叶对射流刚度的影响。采用k-ε标准模型,分析在不同工况下,喷嘴出口的速度分布。在自由射流和增加干扰射流时,将不同方案下喷嘴射流的有效射程S、射流偏转角β、z方向出口速度v_z进行对比。结果表明：在喷嘴内部添加集流导叶能够使射流中心速度提高,集流导叶能够增加射流抗干扰能力,降低速度衰减率,提高射流刚度。通过综合评价得出圆弧形导叶提高射流刚性最优,其后依次为抛物线形、三次曲线形、直线形。

The Impact of Guide Vane on Nozzle Jet Rigidity

The rigidity of nozzle jets has great impacts on the aerodynamic field of the boiler furnace. It can be enhanced by installing collecting guide vanes at the nozzle inlet to make the air more concentrated. In this paper, the impacts of different guide vanes on the jet rigidity are analyzed with Fluent software. By adopting the k-ε model of turbulence, the velocity distributions of the nozzle outlet sections are studied under different operation conditions. Moreover, the effective range S, deflection angle β and velocity component v_z of different nozzles are compared between free jets and disturbed jets. The simulation results show that the collecting guide vanes can increase the jet central velocity, improve the jet anti-jamming capability and reduce the velocity such that the jet rigidity is enhanced. Through comprehensive assessment, it is concluded that the circular arc shaped guide vane has the best performance in rigidity improvement, while in order of performance the other shapes are the parabola curve, the cubic curve and the straight line shaped ones.