分布板对液固流化床换热器颗粒分布的影响

Effect of distributor on particles distribution of liquid-solid fluidized bed heat exchanger

以三维Navier-Stokes方程为控制方程,结合k-ε二方程湍动模型,以直径为1 mm刚玉球作为颗粒相,水为流动相,采用隐式有限体积法对流化床换热器内的液固二项流动进行数值模拟。研究了换热器下管箱安装分布板与否及分布板板面结构形式对颗粒分布的影响,并通过下管箱内压力分布的实验结果对所采用的数值计算方法进行验证。结果表明:下管箱安装分布板可以改善换热管束内颗粒分布的均匀性,且曲面分布板的改善效果优于平面分布板;分布板安装高度比在0.250—0.500时,换热管束内颗粒分布均匀性较好;在安装曲面分布板的情况下,换热管束内的颗粒分布均匀性随着系统初始固含率及下管箱入口流速的增大而增强。压力实验结果和模拟结果误差在20%以内,验证了所选数学模型的准确性。

Based on the three-dimensional Navier-Stokes equations for control and k-ε two-equation turbulence models,with particles（1 mm in diameter） as solid phase and water as flow phase,the two-phase flow in liquid-solid fluidized bed heat exchanger was numerically simulated by implicit finite volume method.The effects of distributor′s existence and structure on particles distribution were studied.The simulation results were verified by pressure distribution experiment of the lower channel.It shows that the existence of distributor improves the uniformity of the particles distribution in the heat exchange tube bundle,and the improving effect of curved distributor is better than that of the plane one.When the installation height ratio is 0.250-0.500,the particles distribution in tube bundle is better.A better distribution is achieved with the increase of initial solids volume fraction and liquid inlet velocity.The results error of pressure experiment and simulation is within 20%,which verifies the accuracy of mathematical model selected.