基于PC-CFB的磨煤机分离器产品细度数值模拟  

Numerical simulation of product fineness of a vertical spindle mill based on PC−CFB technology

作　　者：尚曼霞 姚禹歌 柯希玮 周托 黄中 SHANG Manxia;YAO Yuge;KE Xiwei;ZHOU Tuo;HUANG Zhong(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学热科学与动力工程教育部重点实验室,北京100084

出　　处：《中南大学学报（自然科学版）》2023年第11期4531-4538,共8页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2022YFB4100301)。

摘　　要：为提高磨煤机产品细度、满足粉煤循环流化床(powdered coal-circulating fluidized bed,PC-CFB)对入炉煤粒度的要求,应用稠密离散相模型(dense discrete phase model,DDPM)和颗粒流动力学理论(kinetic theory of granular flow,KTGF)的四向耦合方法,对ZGM80型磨煤机分离器内部的气固流动进行计算。首先,通过计算流场获得分离器内部的速度矢量分布;然后,加入颗粒,研究颗粒在分离器内部的运动行为以及时空分布;最后,对不同通风量下分离器的溢流产率进行计算,获得拆除挡板后分离器的通风特性关系式。研究结果表明:拆除分离器挡板,气体进入分离器内锥体后产生的旋转流动被削弱,切向速度较小,低于8 m/s;颗粒在分离器内粒度分层现象明显,细颗粒上升速度明显比粗颗粒的大。当t=0.6 s时,返料出口开始有颗粒排出;t=5.0 s时,产品与返料2个出口的颗粒质量流率均达到稳定状态,且产品出口粒度分布满足PC-CFB技术的要求。To improve the product fineness of the vertical spindle mill and meet the requirements of powdered coal-circulating fluidized bed on the size of feed coal,a four-way coupling method using dense discrete phase model with kinetic theory of granular flow was adopted to calculate the gas-solid flow inside a ZGM80 vertical spindle mill separator.Firstly,the velocity vector distributions inside the separator were obtained by calculating the flow field.Secondly,particles were added to study their motion behavior and spatiotemporal distributions inside the separator.Finally,the overflow yield of the separator at different air flow rates was calculated to obtain the ventilation characteristics of the vertical spindle mill after removing the baffle.The results show that when the baffle of the separator is removed,the rotational flow of gas entering the inner cone of the separator is weakened,and the tangential velocity is smaller than 8 m/s.The particle size stratification is evident in the separator,and the rising speed of fine particles is higher than that of coarse particles.When t=0.6 s,particles begin to be discharged from the return outlet.When t=5.0 s,the particle mass flow rate of both product and return outlets reaches a stable state,and the particle size distribution at the product outlet meets the requirements of PC-CFB technology.

关 键 词：粉煤循环流化床 磨煤机分离器 细度 DDPM 通风特性 

分 类 号：TK111[动力工程及工程热物理—热能工程]