翅片结构对灰渣颗粒混合效应的影响

Influence of fin structures on mixing effect of ash particles

采用EDEM软件,模拟循环流化床锅炉冷渣管分别采用无翅片、直翅片、直角翅片、大弯角翅片时灰渣颗粒的混合效应;对比分析不同时刻灰渣颗粒的混合指数、单个粒子的循环运动特性以及管壁棱角处颗粒的混合状态。结果表明:在快速混合阶段,直角翅片与大弯角翅片的灰渣颗粒混合指数变化更剧烈,混合时间为20 s时,无翅片、直翅片、直角翅片、大弯角翅片的灰渣颗粒混合指数依次为0.38、 0.41、 0.43、 0.46;在稳定混合阶段,管壁棱角处的混合效应按无翅片、直翅片、直角翅片、大弯角翅片顺序依次增大;从单个颗粒的运动轨迹来看,直角翅片对单个运动颗粒的提升高度最高,但大弯角翅片对单个运动颗粒的提升次数最多;改变翅片结构能明显提高灰渣颗粒混合效应,大弯角翅片结构的混合效应最好。

EDEM software was used to simulate the mixing effect of ash particles when the cold slag tube of circulating fluidized bed boiler adopted non-fin,straight fin,right-angle fin and large-angle fin.The mixing index of ash particles at different times,the cyclic movement characteristics of individual particles and the mixing state of particles at the corners of the tube wall were compared and analyzed.The results show that the mixing index of the ash particles of the right-angled fins and the large-angled fins changes more drastically in the rapid mixing stage.When the mixing time is 20 s,the mixing index of ash particles of no fins,straight fins,right-angle fins and large-angle fins are 0.38,0.41,0.43 and 0.46 in sequence.In the stable mixing stage,the mixing effect at the edges and corners of the tube wall increases in the order of no fins,straight fins,right-angle fins and large-angled fins.From the point of view of the movement path of a single particle,the right-angled fins has the highest lifting height for a single particle,but the large-angled fins has the most lifting times for a single particle.Changing the fin structure obviously improves the mixing effect of ash particles,and the mixing effect of the large-angle fin structure is the best.