基于正交设计的微细颗粒复合凝并建模及仿真

Modeling and Simulation of Fine Particle Composite Coagulation Based on Orthogonal Design

为了研究微细颗粒凝并效率影响因素的敏感性,将颗粒群平衡模型与欧拉多相流模型进行耦合,通过用户自定义函数分别引入布朗凝并、湍流凝并与声波凝并的复合凝并核函数和颗粒凝结增长速率函数,建立了一种适合不同凝并方式特点的复合凝并模型.采用正交设计对微细颗粒的凝并过程进行数值模拟,研究了初始蒸汽饱和度、停留时间、声压级和声频对复合凝并过程的影响程度的主次关系.结果表明,该复合凝并模型能有效地表征PM2.5颗粒凝并效率.通过PM10和PM2.5凝并效率正交模拟试验进一步得出,复合凝并作用下各参数的影响程度均为:声压级>停留时间>初始蒸汽饱和度>声频.声压级、停留时间和初始蒸汽饱和度的增大有利于凝并效率的提高,而声频则存在一个最佳值使得凝并效率达到最高,且PM2.5凝并效率的最佳频率比PM10高.该模型的建立对研究微细颗粒物复合凝并相关因素的影响程度具有重要作用.

In order to study the sensitivity of factors affecting the coagulation efficiency of fine particles,a compo- site coagulation model suitable for different coagulation approaches was established,coupling the particle goup po- pulation balance model with the Euler s multiphase flow model and using the user-defined function to simultaneously introduce the Brownian-turbulent-acoustic composite coagulation kernel function and the condensation growth rate function.The numerical simulation of fine particle composite coagulation process was performed by using orthogonal design,and the primary and secondary relations of the effect of initial steam supersaturation,residence time,sound pressure level and sound frequency on the coagulation process were analyzed based on the simulation results.The simulation results show that the model can effectively characterize the coagulation efficiency of PM 2.5 particles.Through orthogonal simulation tests of coagulation efficiency of PM 10 and PM 2.5 ,it is further concluded that the influence degree of each parameter under composite coagulation is:sound pressure level > residence time > initial steam saturation > sound frequency.The increase of sound pressure level,residence time and initial steam saturation is conducive to the improvement of coagulation efficiency,while there is an optimal value of sound frequency to maximize the coagulation efficiency,and the optimal frequency of PM 2.5 coagulation efficiency is higher than that of PM 10 .The establishment of the model is significant to the research on the influence degree of correlation parameters for fine particle composite coagulation.