水平液固循环流化床换热器传热性能评价

Evaluation on heat transfer performance of horizontal liquid-solid circulating fluidized bed heat exchanger

对管内插入Kenics静态混合器的水平液固循环流化床换热器进行实验研究,实验考察了静态混合器扭率、静态混合器安装方式、液体流速、颗粒体积分数对传热性能和流阻性能的影响,并运用综合强化传热性能评价指标（PEC）对其进行分析。实验发现,传热性能和阻力系数均随扭率增加而减小。当雷诺数在10000-45000之间时,扭率为1.5、2、2.5、3.5的Kenics静态混合器的PEC指标均大于1,说明了水平流化床换热器插入Kenics静态混合器能够改善传热。在雷诺数达到25000左右、Kenics静态混合器扭率为2.5、颗粒体积分数为4%时,水平流化床换热器的PEC指标最高达到1.18。当两个扭率均为2.5的Kenics静态混合器安装间距为200mm时,水平流化床换热器的PEC指标最高。

The horizontal liquid-solid circulating fluidized bed heat exchanger with Kenics static mixer was studied by this experiment. The effects of Kenics static mixer twist rate,the installation method of Kenics static mixer,flow rate and particle volume fraction on heat transfer performance and flow resistance performance were investigated,which were analyzed by the comprehensive heat transfer performance evaluation criteria index. It was found that the heat transfer and resistance coefficient decrease with the increase of twist rate. Results showed that the performance evaluation criteria of Kenics static mixer with twist rate Y=1.5,2,2.5,3.5 were over 1 without exception in the range of Reynolds number 10000—45000,which indicates that the horizontal fluidized bed heat exchanger with Kenics static mixer can enhance heat transfer. The performance evaluation criteria of horizontal fluidized bed heat exchanger reached 1.18 at most,when the Reynolds number reached about 25000,the twist rate of Kenics static mixer is Y=2.5 and the particle volume fraction is 4%. The performance evaluation criteria of horizontal fluidized bed heat exchanger is the highest on the condition that the distance between two Kenics static mixers with twist rate Y=2.5 is 200 mm.