摘要
湍流聚并技术是去除燃煤烟气细颗粒物的有效手段之一。为了弄清聚并器结构和烟气颗粒特征对烟气湍流聚并的影响,采用数值模拟方法,考察了3种聚并元件结构(分别为一般圆柱体、带方翼圆柱体和V型钝体)和3种烟气颗粒粒径分布模式(分别为大小颗粒混杂、纯大颗粒和纯小颗粒)下的聚并效果。结果表明:方翼结构和V型钝体结构均能提升流场的涡量和湍动能耗散率,从而促进颗粒碰撞和聚并发生;与方翼结构相比,V型钝体结构的压降损失更小,聚并效果更好;细颗粒物的消除主要发生在聚并元件尾部生成涡的区域内,而在下游区域则较少发生碰撞和聚并;当来流中既有大颗粒又有小颗粒时,大、小颗粒之间的碰撞明显加强,聚并效果提升。以上研究结果可为聚并器的设计提供理论依据,并为湍流聚并技术在锅炉烟气细颗粒物去除中的应用提供参考。
The turbulent aggregation is an effective method to remove fine particles in coal-fired flue gas.To clarify the effect of aggregator structure and the characteristic of fine particles on flue gas turbulent aggregation,three element structures(normal cylinder,square-winged cylinder and V-shaped bluff body)and three inlet particle size distributions(mixed large and small particles,pure large particles and pure small particles)were numerically studied through numerical simulation.The results showed that both the square wing and the Vshaped bluff body could increase the vorticity and dissipation rate of turbulent kinetic energy,thus promote particle collision and aggregation.Comparing to the square wing,the V-shaped bluff body performs better with a much lower pressure loss.The reduction of fine particles mainly occurred in the small-eddy formed region of the element where the turbulent dissipation rate was high.However,in the downstream region,particle collision and aggregation occurred hardly.When large and small particles coexisted in influent,the collision between them was evidently strengthened,aggregation effect was improved and thus the removal efficiency of fine particles was greatly elevated.The above research lays a solid theoretical foundation for the design of practical aggregator and provides a reference for the application of turbulent aggregation in the reduction of fine particles in flue gas.
作者
王国昌
刘玺璞
米建春
WANG Guochang;LIU Xipu;MI Jianchun(College of Enginecring,Peking University,Beijing 100871,China;Xi'an Thermal Power Research Institute Co.Ltd.,Xi'an 710054,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2021年第1期253-261,共9页
Chinese Journal of Environmental Engineering
基金
国家重点研发计划(2016YFB0600605)。
关键词
细颗粒物
湍流聚并
元件结构
来流颗粒粒径
分离涡模型
离散群方法
fine particles
turbulent aggregation
element structure
inlet particle size
detached eddy model
discrete group method
