基于数值模拟的静态混合器混合性能对比

Comparison of Mixing Performance of Static Mixers Based on Numerical Simulation

构建长度、直径相同的SK、SX型静态混合器,利用Polyflow软件模拟低密度聚乙烯(LDPE)熔体在静态混合器内的流动情况,得到2种静态混合器的示踪粒子分布图、压降、分离尺度等参数,分析了流量对压力和分离尺度的影响,以及分离尺度下降一半,2种静态混合器所需的压降和流程长度。结果表明,随流程长度的增大,SX型静态混合器的粒子分布更加均匀,分离尺度更小,在出口处分离尺度约为SK型的1/3;当流量增至初始值的10倍时,SK和SX型的压降分别增至原来的7.4和4.7倍,两者出口处的分离尺度分别变化了8.3%和60%;随着混合过程的进行,分离尺度每下降1/2,所需压降及流程长度逐渐增大。

The static mixers of SK and SX with the same length and diameter were constructed,and then the flow of low-density polyethylene(LDPE)melt in the static mixer was simulated by using Polyflow software.The distribution of tracer particle,separation scale,and pressure drop were obtained.The effect of flow rate on pressure drop and separation scale were analyzed emphatically,as well as pressure drop and the flow length required to reduce the separation scale by half were compared for two static mixers.The results showed that,with the increase of flow length,the distribution of tracer particle in the SX static mixer was more uniform and the separation scale at the outlet of SX static mixer was about one third of that of the SK static mixer.While increasing flow rate to 10 times,the pressure drops of SK and SX static mixer increased to 7.4 and 4.7 times,respectively,as well as the separation scales of them changed by 8.3%and 60%,respectively.With the progress of the mixing process,the required pressure drop gradually increased and the required process length gradually increased for each reduction by half of the separation scale.