DBEL型W火焰锅炉燃尽风喷口设计

Design of the OFA(Over-fired Air) Spout of a DBEL(Doosan Babcock Energy Limited) Type W-shaped Flame Boiler

三井巴布科克公司的W火焰锅炉技术,受锅炉结构及风箱位置等因素的制约,使得内直流外旋流的燃尽风喷口不能设置单独的调节装置调节旋流强度,故对燃尽风喷口的结构设计提出更高的要求。利用冷态模化试验和CFD数值模拟软件获得燃尽风喷口的阻力特性和流动特性。使燃尽风与锅炉的热工过程相匹配,实现封闭主流烟气,保证燃烧效率的作用。应用结果表明:当叶片与轴线的夹角为25°-30°时,燃尽风喷口出口射流的旋转动量矩衰减较慢,旋转动能可有效传递至炉膛中心,使得此处的可燃物质与空气充分混合,保证燃尽度。

The W-shaped flame boiler technology developed by Doosan Babcock Co. Ltd. makes it impossible to set up a separate regulation device to regulate the swirling intensity at the OFA spout forming an once-through flow inside and swirling flow outside due to the restriction of such factors as the structure of the boilers and the location of the air box and in such a case,a higher requirement is set for the design of the structure of the OFA spout. By utilizing the cold-state modeling test and the CFD numerical simulation software,the authors obtained the resistance and flow characteristics of the OFA spout,making the OFA to match with the thermal process of the boilers and realize the aim of enclosing the mainstream flue gases and securing the combustion efficiency. The application results show that when the inclusive angle of the blades and the axial line is 25° to 30°,the rotating momentum torque of the jet flowat the outlet of the OFA spout will attenuate relatively slow and the rotating kinetic energy can be effectively transferred to the furnace center,thus making the combustible substances and air thereto sufficiently mixed and ensuring a burn-out degree.