立管内椭球颗粒群强化传热特性模拟研究

Simulation study on enhanced heat transfer characteristics of ellipsoidal particle group in vertical tube

为提高液固两相流传热效率,通过添加椭球形颗粒改善立式换热管内液固两相流分布,采用CFD-DEM数值模拟颗粒长径比β、颗粒进口体积分数φ以及流体进口速度v与管内椭球形颗粒群传热的关系,并根据PEC指数评价颗粒强化传热能力。模拟结果表明:在1.50≤β≤2.50,2.00%≤φ≤4.00%,1.0 m/s≤v≤1.5 m/s时,椭球形颗粒PEC指数总高于球形颗粒,即前者强化换热效果优于后者。

In order to improve the heat transfer efficiency of the liquid-solid two-phase flow heat exchange equipment,the CFD-DEM numerical simulation of the liquid-solid two-phase flow in the vertical heat exchange tube was carried out by adding ellipsoidal particles.Based on the particle distribution in the tube,the effect of particle aspect ratioβ,particle inlet volume fractionαand fluid inlet velocity v on the heat transfer characteristics of the ellipsoidal particle group in the tube is studied,and the enhanced heat transfer capability of the particles is evaluated according to the PEC index.The simulation results show that in the parameter range of 1.50≤β≤2.50,2.00%≤φ≤4.00%and 1.0 m/s≤v≤1.5 m/s,the PEC index of ellipsoidal particles is greater than that of spherical particles,that is,the ellipsoidal particles have greater enhanced heat transfer ability that spherical particles.