化工学报 ›› 2021, Vol. 72 ›› Issue (4): 1939-1946.DOI: 10.11949/0438-1157.20201030

• 流体力学与传递现象 • 上一篇    下一篇

基于离散元方法的高碱煤灰沉积过程数值模拟研究

金默(),刘道银,陈晓平()   

  1. 东南大学能源转换及其过程测控教育部重点实验室,江苏 南京 210096
  • 收稿日期:2020-07-28 修回日期:2020-10-12 出版日期:2021-04-05 发布日期:2021-04-05
  • 通讯作者: 陈晓平
  • 作者简介:金默(1996—),男,硕士研究生,3023954394@qq.com
  • 基金资助:
    国家自然科学基金项目(51776040)

Numerical simulation research of high-alkali coal ash deposition process based on discrete element method

JIN Mo(),LIU Daoyin,CHEN Xiaoping()   

  1. Key Laboratory of Thermal Energy Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096, Jiangsu, China
  • Received:2020-07-28 Revised:2020-10-12 Online:2021-04-05 Published:2021-04-05
  • Contact: CHEN Xiaoping

摘要:

针对锅炉燃用高碱煤产生的受热面积灰问题,以流化床锅炉对流过热器为研究对象,采用离散元方法(discrete element method)建立黏性颗粒碰撞黏附模型,对过热器对流受热面的积灰过程进行数值模拟。分别研究了烟气流速、颗粒粒径、烟气温度以及壁面温度对积灰特性的影响规律。模拟结果表明:烟气流速增大、颗粒粒径减小会导致颗粒的碰撞率上升、捕集率下降;烟气温度和壁面温度提升时,颗粒表面能上升,导致颗粒捕集率上升,且壁面温度的影响更为显著;不同工况下最大积灰厚度、沉积物形状变化较小。

关键词: 高碱煤, 流化床, 离散元方法, 数值模拟, 沉积物

Abstract:

Burning high-alkali coal causes ash deposition on heat transfer surface. To visualize the deposit growth process, the numerical simulation of fouling process was carried out on fluidized-bed boiler convection super heater using sticky particle collision adhesion model based on discrete element method. The influences of gas velocity, particle diameter, gas temperature and wall temperature to ash deposition characteristics were studied and compared with existing research results. The simulation results indicated that the collision efficiency increased and capture efficiency decreased with the increase of gas velocity and the decrease of particle diameter. The increase of particle surface energy caused by the increase of gas and wall temperature led to the increase of capture efficiency while the influence of wall temperature was more obvious. The maximum deposition thickness and the shape of deposition under different working conditions have little change.

Key words: high-alkali coal, fluidized-bed, discrete element method, numerical simulation, deposition

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