摘要
沉降室是余热锅炉中关键的除尘部件,在锅炉运行过程中,进入沉降室的换热烟气会夹杂大量烟气颗粒,高速的烟气颗粒撞击烟道壁面,造成了烟道壁面的磨损。基于EDEM-Fluent耦合计算的方法研究了余热锅炉沉降室内烟道的磨损特性,设置烟气流含尘浓度为55 g/Nm^(3),烟气颗粒粒径为1 mm,密度为2500 kg/m^(3)。对比分析了0.8V_(t)、1.0V_(t)和1.2V_(t)(V_(t)为进气速度)3种不同进气负载下烟道各截面的流场特性与烟道内的颗粒分布,同时引入Archard磨损模型得到烟道各部位的磨损量分布。结果表明:二号灰斗的相对磨损量从28%增加到37%,挡灰板上部的相对磨损量由20%增加到27%,而一号灰斗的相对磨损量从17%下降到9%。磨损量变化的原因可归因于烟气流速和颗粒分布的变化。烟气流从入口处进入沉降室后速度先增加后降低,在二号灰斗以及挡灰板处流速达到最大值,且二号灰斗处形成了纵向的旋流,一部分颗粒随烟气流快速上升与壁面发生碰撞,这使得在各工况下,二号灰斗的处的磨损程度均明显大于其余部位。同时负载的增加还使得颗粒的分布呈现向三号灰斗处积聚的趋势,从一号灰斗处沉降的颗粒减少,磨损量降低。大量积聚的颗粒与三号灰斗壁面的碰撞使得三号灰斗的磨损量增加。
The sedimentation chamber is a key dust removal component in waste heat boilers,during boiler operation,the heat-exchange fumes entering the subsidence chamber mixes with a large number of dust particles,high-speed dust particles hit the flue wall,resulting in the wear of the flue wall.Based on the EDEM-Fluent coupling method,the flue wear characteristics in the settling chamber of the waste heat boiler was studied.The dust concentration in the flue gas stream was 55 g/Nm^(3),the particle size of the flue gas was 1 mm,the particle density was 2500 kg/m^(3).The flow field characteristics of each section and the particle distribution in the flue under three different intake loads of 0.8V_(t),1.0V_(t) and 1.2V_(t)(V_(t) is the intake speed)were comparative analyzed.At the same time,the Archard wear model was introduced to obtain the wear distribution and wear law of each part of the flue.The results show that the relative wear of the second ash hopper increased from 28%to 37%,the relative wear of the upper part of the ash baffle increased from 20%to 27%,and the relative wear of the first ash hopper decreased from 17%to 9%.The reason for the change in the amount of wear can be attributed to the change in the flue gas flow rate and particle distribution.After the flue gas flow enters the sedimentation chamber from the entrance,the velocity first increases and then decreases.The flow velocity reaches the maximum at the second ash hopper and the ash baffle,and a longitudinal swirling flow is formed at the second ash hopper,and some particles follow the flue gas flow.The rapid ascent collides with the wall,which makes the wear degree of the No.2 ash hopper obviously greater than the rest of the parts under all working conditions.At the same time,the increase in the load also makes the distribution of particles show a tendency to accumulate in the No.3 ash hopper,and the number of particles settled from the No.1 ash hopper is reduced,and the amount of wear is reduced.The collision of a large amount of accumulated particles with the wall of the No.3 ash hopper increases the wear of the No.3 ash hopper.
作者
李科宏
王佳
何庆中
赖镜安
赵苾通
左超
何润东
LI Ke-hong;WANG Jia;HE Qing-zhong;LAI Jing-an;ZHAO Bi-tong;ZUO Chao;HE Run-dong(School of Mechanical Engineering, Sichuan University of Science and Engineering, Yibin 644000, China)
出处
《科学技术与工程》
北大核心
2022年第12期4812-4819,共8页
Science Technology and Engineering
基金
四川省教育厅创新团队项目(17TD0026)
“双千计划”资助项目(2017CC0046)
四川轻化工大学研究生创新基金(y2020008)。