摘要
针对粉体换热器传热系数低的现象,探索采用改变主导热阻的方法提高粉体换热器传热系数.文章设计了圆弧通道和直板通道研究粉体与水冷壁面之间的对流换热,用水冷滚筒研究滚筒冷渣机内高温粉体与滚筒之间的换热能力.研究结果表明:粉体与水冷金属壁面之间的对流换热系数远大于同等条件下的接触导热为主导热阻的换热系数;滚筒颗粒床中存在难以冷却的高温核心区;高温核心区的存在,致使换热器设计使用的对数平均温差概念失去物理基础,不能反映粉体换热器的工作过程;决定滚筒冷渣机换热能力的是靠近水冷壁面的灰渣温度与水冷壁面温度的温度差.
Aiming at the phenomenon of low heat transfer coefficient of powder heat exchanger,the method of changing the dominant thermal resistance was explored to improve the heat transfer coefficient of powder heat exchanger.In this paper,circular arc channel and straight plate channel were designed to study the convective heat transfer between powder and water-cooled wall,and the heat transfer capacity between high-temperature powder and water wall in rotary drum ash cooler was studied by water-cooled drum.The results show that the convective heat transfer coefficient between powder and water-cooled metal wall is much greater than that dominated by contact heat conduction under the same conditions.This conclusion can greatly improve the heat transfer coefficient of powder heat exchanger.The water-cooled drum experiment shows that there is a high-temperature core which is difficult to cool in the drum particle bed.The existence of high temperature core makes the concept of logarithmic average temperature difference used in heat exchanger design lose its physical basis and cannot reflect the working process of rotary drum ash cooler.The heat exchange capacity of rotary drum ash cooler is determined by the temperature difference between the ash temperature near the water wall and the water wall temperature.
作者
刘柏谦
LIU Baiqian(Department of Energy and Environmental Engineering, University of Science and Technology Beijing,Beijing 100083,China)
出处
《徐州工程学院学报（自然科学版）》
CAS
2022年第1期47-53,共7页
Journal of Xuzhou Institute of Technology(Natural Sciences Edition)
关键词
粉体
传热
换热器
滚筒
powder
heat transfer
heat exchanger
rotary drum
