ISA 炉余热锅炉水平烟道流场、温度场优化模拟

余热锅炉是工业上回收烟气余热的重要设备，其换热效率的高低与烟道内部温度场分布密切相关. 某公司的ISA炉余热锅炉，其结构呈三段式（上升烟道-下降烟道-水平烟道），烟气由下降烟道进入水平烟道后，受惯性作用，主要从对流换热区下部经过，难以充分发挥对流换热区的功能. 作者借助数值模拟的手段，在下降烟道与水平烟道连接处添加导流装置，强制引导烟气流向对流换热区.模拟结果表明，添加导流装置后，水平烟道竖直方向速度场分布趋于均匀:速度范围介于2.0~3.5 m/s的区域扩大，而大于3.5 m/s与小于2.0 m/s的区域相对减小，且速度最大值与最小值均有所收缩.单位时间内，进入对流换热区热量由5.27 MJ提升为7.70 MJ，而进入灰斗的热量由4.89 MJ减少为2.90 MJ. 同时，回流现象减弱，水平烟道上部回旋低温区范围缩小，有利于避免低温腐蚀的发生. 

Optimum simulation of velocity field and temperature field of horizontal passage of ISA waste heat boiler

Waste heat boiler (WHB) is important equipment recovering waste heat of the flue gas in industry, the recovery efficiency of the WHB is closely related with its internal temperature field distribution. The ISA WHB has a three-passage structure (rising passage-descending passage-horizontal passage), and exhaust gas, after entering from the descending passage, flows underneath the convection banks in the horizontal passage, under the effect of inertia, which has an adverse effect on heat exchange of the horizontal passage. With the help of the simulation method, a flow guide plate was installed around the corner to lead the gas to convection banks. The results show that with the help of the plate, the distribution of velocity in the horizontal passage tends to uniform:the range from 2.0 m/s to 3.5 m/s is expanded, and the maximum and minimum of the velocity are both contracted. The flow rate of enthalpy through convection banks rises from 5.27 MJ to 7.70 MJ, while the flow rate of enthalpy through underneath the banks declines from 4.89 MJ to 2.90 MJ. At the same time, the district of low temperature caused by backflow is narrowed, which is beneficial to low temperature corrosion.