预混器的工艺计算和数值分析

Process design and numerical analysis of premixer

根据热解焚烧理论,废物燃烧时会产生热解气体,利用工艺设计方法对热解气的组分以及质量进行计算。同时,得到足够的二次风量,使热解气可以完全燃烧。利用Workbench有限元分析软件,建立预混器流场的数值分析模型,分析热解气和二次风在设备内的混合情况。结果表明:预混器能够起到较好的气体混合效果,设备设计方法是合理的。此外,为了提高设备性能、优化设计,通过改变相关的结构尺寸,研究了设计参数对设备性能的影响。结果发现,缩小混合进口尺寸可以提高二次风的流速,增加混合进口数量能够得到更加均匀的混合效果,选择适当的流道尺寸可以保持合理的热解气流速,而增加预混器的长度则延长了气体的停留时间,均有利于提高预混器的混合性能。

According to the theory of pyrolysis incineration,burning waste can produce pyrolysis gases.By process design method,the composition and flux of pyrolysis gases were calculated.At same time,enough secondary airflux was obtained,so that pyrolysis gases can fully burn.By Workbench finite element analysis software,the numerical analysis model of premixer flow field was established.Thus,mixing effect between pyrolysis gases and secondary air can be analyzed.The results show that premixer has a good mixing effect and the design method is reasonable.In addition,in order to improve the performance and optimize the design,by changing relative structure sizes,the influence of design parameters on device performance was researched.It is found that decreasing the size of mixing entrances can enhance secondary air velocity,increasing the amount of mixing entrances will get more homogeneous mixing effect,choosing suitable the size of passageway is able tomaintain reasonable pyrolysis gases velocity and adding the length of device may lengthen gases standing time.All of these can advanced the mixing performance of device