中伸式喷嘴同轴圆湍射流近场区流场的数值模拟  

Numerical simulation for the near flow field of the center-jutting turbulent coaxial effluent with a center-jutting nozzle

作　　者：洪俊[1] 刁永发[1] 

机构地区：[1]东华大学环境科学与工程学院,上海201620

出　　处：《安全与环境学报》2016年第4期181-185,共5页Journal of Safety and Environment

基　　金：国家"863"高技术研究发展计划项目(2008AA05Z305);上海市优秀技术带头人计划项目(14XD1424700);中央高校基本科研业务费重点项目(11D11315)

摘　　要：中伸式同轴射流喷管应用于脉冲袋式除尘器可以增大脉冲射流的卷吸气量[1]。运用Fluent软件中的大涡模拟(LES)方法模拟了传统同轴射流和3种中伸式喷嘴同轴射流的近场区流场特性,中伸式喷嘴的长度L分别为2.5Di、5Di、7.5Di,Di为中心射流管管径,中心射流的Re为4 470。结果表明:中心射流管中伸长度在2.5Di的工况下,中心射流的核心长度与传统同轴喷管中心射流的核心长度相差不大;随中心射流管中伸长度增加,射流的核心长度变短,径向速度衰减更快,并且湍动能分布更加不稳定;随中心射流管中伸长度增加,轴线上距中心射流管喷嘴相同距离处的监测点的速度功率频谱波峰值增大,且波峰值所对应的频率减小;在相同中伸长度工况下,随距中心射流管喷嘴距离增加,监测点的速度功率频谱的波峰值增加,波峰值对应的频率没有变化。In this article,we have been attempting to apply the large eddy simulation technique in the effluent software to the exploration of the characteristic features of the traditional coaxial jet tube and its flow in the neighboring field zone with three different center-efflux nozzles. The length L of the diameter of the central tube has its Re number of the central jet being 4470 with the lengths of its three mid-jutting nozzles being 2. 5Di,5Di,7. 5Di respectively. The function of the coaxial jet tube with the mid-jutting nozzle is to increase the amount of the gas entering the jet as a pulse bag filter. The results of the experiment indicate that,in the condition when the extended length of the central tube is2. 5Di,little difference can actually be found between the central inner-jet and the traditional coaxial tube in their central length.However,with the increase of the length of the central efflux nozzle,the core length of the jet gets shorter,whereas the velocity in the radius direction tends to delay quickly,though the distribution of the turbulent kinetic power is more unstable. In that case,when the central tube gets extended,it would have to move a larger distance to the outer jet. And,when it moves to the field at the same distance to the nozzle of the central tube,the flow field of the outer jet would develop more comprehensively,while the velocity distribution in the radius direction can likely turn to be more undulate,whereas the turbulent kinetic energy of the exterior jet becomes more unstable and in turn more influential to the inner-jet. What is more,with the increase of the length of the central tube,the innerjet from the laminar flow to the turbulent flow may get easier while the spectral density of the maximal power of the point turns to be greater at the same distance to the nozzle of the central tube on the axis. Thus,it be possible for the maximum spectral power intensity to become smaller. Thus,as a result,with the length of the central tube being constant,the frequency of the maximum power

关 键 词：安全工程 LES 中伸式喷嘴 同轴射流 脉冲袋式除尘器 

分 类 号：X933.7[环境科学与工程—安全科学]