狭长空间内细水雾射流的数值仿真  

Numerical simulation of atomized water jets in a narrow space

作　　者：杜扬[1] 齐圣 欧益宏[1] 张培理[1] 何东海[1] 

机构地区：[1]中国人民解放军后勤工程学院军事供油工程系,重庆401331

出　　处：《安全与环境学报》2014年第6期65-69,共5页Journal of Safety and Environment

基　　金：国家自然科学基金项目(51276195);重庆市自然科学基金项目(cstc2012jj A900015)

摘　　要：综合可压缩流场控制方程、κ-ε湍流模型、粒子动力学模型及简化的雾滴-壁面碰撞模型,建立了狭长空间内细水雾射流的数值仿真模型。基于该模型,采用Fluent流体动力学仿真软件对4种不同粒度的细水雾射流进行了数值仿真。结果表明:粒度较大的细水雾在入射初期速度较快,且保持雾化角的能力更强;细水雾在到达壁面后形成的雾化区形态上保持准稳定,呈现出特征鲜明的雾化主流区、横流区、回流区与涡流区,整个雾化区范围向两侧匀速延伸,粒度越小的雾化区延伸速度越快;狭长空间内垂直于射流方向的气流与细水雾射流产生相互影响,气流在远离喷口的雾化区迎风处速度降低,在靠近喷口的背风处形成涡流,雾化区形态沿气流流向发生扭曲。The given paper is to introduce a simulated research of the concentration distribution of the spray in a narrow space formed by an atomized water jet in a numerical approach. The simulated computa- tional model is supposed to use the medium as a two-phase mixture made of an ideal gas （representing the air in the narrow space） and a bunch of tiny droplets with their initial speed of 10 m/s （representing the atomized water jet）. On the one hand, the gas phase can be modeled by a compressible, time-dependent governing equation and the RNG k -e turbulence model, on the other hand, the droplets can be modeled as some moving points, interacting with the gas effluents. The computational domain size is 1 600 mm× 200 mm and the grid size is 5 mm × 5 mm. In order to investigate the effects of the diameters of the droplets, it is supposed to consider the four different diameters to be 50 μm, 75 μm, 100 μm and 125 μm. The results of our simulation indicate that the spray angle of the jet flow may not be a constant. At the beginning, the spray angle is supposed to be approximately equal to the initial value. As the jet is moving towards the bottom of the computational domain, the spray angle tends to de- crease due to the effect of the backflow on either of the two sides. The spray angle is supposed to change more noticeably in the case of droplets of smaller diameters, because of their smaller inertias. For the same reason, the droplets with smaller diameters tend to lose more momentum when interacting with the gas phase and hence the jet flow moves slower. As is known, the atomized water jet can form an atomized area in the space. This study indicates that when the jet flow reached the bottom level, the atomized area will become quasi- steady in shape, which can be differentiated into four zones （the main flowing zone, the transverse flowing zone, the back flowing zone and eddy zone）. At this moment, the continually entering droplets help to broaden the atomized area without changing their shape dramatical

关 键 词：安全工程 细水雾射流 狭长空间 离散相模型 数值模拟 

分 类 号：X928.7[环境科学与工程—安全科学]