颗粒性质对颗粒污垢成垢影响的数值模拟研究

Numerical Simulation of Particle Fouling on the Heat Exchange Surface Under Different Particle Properties

为了探究颗粒性质对换热面上颗粒污垢成垢过程的影响,本文建立了颗粒污垢沉积和剥蚀模型,采用计算流体力学(computational fluid dynamics,CFD)方法,借助Fluent软件,对不同颗粒性质条件下颗粒污垢的沉积过程进行了数值模拟。结果显示,颗粒污垢热阻先增加后平稳,一段时间后达到一个渐近值。随着颗粒密度的增大,结垢速率逐渐减缓,但由于物性参数不同,污垢热阻值呈现不同的变化规律;随着颗粒粒径的增大,结垢速率逐渐减缓,污垢热阻渐近值随之增大;随着颗粒浓度的增大,结垢速率逐渐加快,污垢热阻渐近值也随之增大。由数值模拟结果可知,减小颗粒浓度和粒径可减缓结垢速率,减小污垢热阻渐近值;颗粒种类对污垢热阻的影响较大。该方法对研究污水中多种颗粒沉积规律具有重要意义。

To study the influence of particle property to fouling forming,an deposition and scaling model is set up.A processing of particle fouling under conditions of different particle properties is simulated in Fluent with the method of CFD.The results showed that the thermal resistance of particle fouling increased firstly and then stabilized,and reached an asymptotic value after a period of time.With the increase of particle density,the scaling rate gradually slowed down,but because of the different physical parameters,the fouling resistance values have different variations.The fouling rate gradually slowed down with the increase of particle size,and the asymptotic value of fouling resistance increases.With the particle concentration increased,the fouling rate gradually accelerated which leads to increasing of the asymptotic value of fouling resistance.The calculated results indicate that the decrease of the particle concentration and particle size reduction can reduce the fouling rate and fouling asymptotic values,so the effect of particle types on the fouling resistance is large.It is very important to study the deposition law of various particles in the presence of sewage.