基于射流动力学特征的协流喷管的数值研究  

Numerical Investigation of Co-flow Nozzles Based on Dynamic Characteristics of Jet

作　　者：何明礼 章光[2] 胡少华[2] 王成 HE Mingli;ZHANG Guang;HU Shaohua;WANG Cheng(School of Environmental Science and Engineering,Hubei Polytechnic University,Huangshi 435000,China;School of Safety Science and Emergency Management,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]湖北理工学院环境科学与工程学院,黄石435003 [2]武汉理工大学安全科学与应急管理学院,武汉430070

出　　处：《工程热物理学报》2023年第10期2647-2656,共10页Journal of Engineering Thermophysics

基　　金：湖北理工学院引进人才项目资助(No.22xjz11R);国家自然科学基金资助项目(No.52074202)。

摘　　要：为合理确定协流喷管的设计参数,采用数值仿真方法研究了喷管结构(拉瓦尔、直管、曲线收缩、直线收缩)和工作压力(过膨胀、刚好膨胀、欠膨胀)对流场动力学特征(射流的速度、扩散性、卷吸和动能)的影响。研究表明:拉瓦尔喷管和直管产生的射流其速度和动能衰减较慢,扩散和卷吸较弱;射流轴向速度衰减速率、扩散率和动能衰减速率与工作压力负相关;射流卷吸常数随工作压力升高而增大,但当喷管出口处于刚好膨胀或过膨胀状态时,卷吸常数趋于某一特定值,值的大小与喷管结构相关。协流细水雾灭火系统的协流喷管结构采用拉瓦尔喷管和直管能够得到更好的协流效果。To determine the design parameters of the co-fow nozzle,the effects of nozzle structures(i.e.Laval,pipe,straight line and curve contraction)and working pressure(i.e.over expanded,perfectly expanded,under expanded)on the dynamic characteristics(i.e.velocity,diffusivity,entrainment,kinetic energy of the jets)of the fow field were studied by numerical simulation.The results show that the jets issuing from the Laval and the pipe have slower velocity decay and kinetic energy dissipation,weak diffusion and entrainment.The axial velocity decay,diffusivity,and kinetic energy dissipation are negatively correlated with the working pressure.The entrainment constant decreases as the working pressure increases.However,it appears that,the profiles of the entrainment constant converge to a single curve for the nozzle outlet perfectly expanded or under expanded,but the asymptotic values are related to the nozzle structures.Therefore,the Laval and the pipe are more suitable for the co-flow nozzle of a co-flow jet water mist fire extinguishing system.

关 键 词：数值仿真 喷管结构 工作压力 动力学特征 可压缩射流 

分 类 号：X932[环境科学与工程—安全科学]