基于改进型进气口结构的循环烟罩数值模拟

Numerical simulation of flue gas circulation hood based on improved air inlet structure

中国钢铁行业能源消耗巨大,为解决烧结过程中能源消耗高、污染排放量大等问题,对某钢铁企业196 m2烧结机烟气循环系统进行研究,建立三维物理模型,将其作为整个计算域进行模拟仿真。模拟发现在现有生产条件下无任何导流装置的烟气循环罩内,来流烟气速度过大且其聚于一点、进而向外扩散的方式会导致烟罩内产生大量的低速回流区,不利于烟气的均匀分布。通过改进烟气循环罩结构,引入浸入式水口理念并与烧结烟气循环罩有机结合,以实现烟气的分流和均匀分布。结果表明,相较于原烟气循环罩结构,改进进气口结构后,中心来流偏斜度减小了85%,进入烧结料层的最高流速为3.1381 m/s;烧结料层水平截面的速度方差为0.36,相比于原结构降低了84.1%;改进后的结构消除了烟气偏斜和料面速度过大的问题,烟气循环罩内烟气分布均匀,改进型进气口结构与烧结烟气循环罩协同作用,使得烟气和料层能够更有效的交互,进而得到更高的烧结效率和更少的废气排放。

Iron and steel industry has huge energy consumption in China,in order to solve the problems of high ener-gy consumption and large pollution emissions in the sintering process,the flue gas circulation system of 196 m'sin-tering machine of a steel enterprise was studied,and a three-dimensional physical model was established,which was used as the entire calculation domain for simulation.The simulation found that under the existing production condi-tions,the incoming flue gas velocity was too high in the flue gas circulation hood without any diversion device,and the way it gathered at one point and then diffused outward would cause a large number of low-speed recirculation ar-eas in the hood,which was not conducive to the uniform distribution of flue gas.By improving the structure of the flue gas circulation hood,introducing the concept of submerged nozzle and organically combining it with the sintering flue gas circulation hood,the diversion and uniform distribution of flue gas can be achieved.The results show that,compared with the original flue gas circulation hood structure,after improving air inlet structure,the central flow deflection is reduced by 85%,and the maximum flow velocity entering the sintering material layer is 3.1381 m/s;the velocity variance of the horizontal section for sintering material layer is 0.36,which is reduced by 84.1%com-pared with the original structure;the improved structure eliminates the problems of flue gas deflection and excessive material surface velocity,and the flue gas is evenly distributed in the flue gas circulation hood.The improved air in-let structure works synergistically with the sintering flue gas circulation hood,so that the flue gas and the material layer can interact more effectively,thereby obtaining higher sintering efficiency and less waste gas emissions.