摘要
为更好研究迷宫流道滴头的内流场水力性能和颗粒运动特性,该文采用k-ε模型和Eulerian-Lagrangian两相流模型进行了一系列数值研究。首先,通过3种湍流模型(标准k-ε、RNG k-ε与Realizable k-ε)预测迷宫流道滴头水力特性并与喻黎明等(2009)的试验结果对比分析,标准k-ε模型更适合于模拟迷宫流道滴头的内流场,与PIV试验数据相比,水力性能曲线平均模拟误差仅为2.32%。然后,基于Lagrangian的颗粒离散相模型,数值研究了齿形迷宫流道内不同密度和直径的单个颗粒运动轨迹及运动特性,并与喻黎明等(2009)的相关试验数据比较,结果表明,考虑了重力、浮力、虚拟质量力和曳力的随机轨道模型能够更加准确地模拟颗粒在迷宫流道内的运动,与PIV试验数据相比,颗粒运动速度后平均模拟误差仅为2.34%。颗粒直径变化较密度变化对颗粒运动影响大,随着颗粒直径或密度增大,颗粒运动速度减小,颗粒速度变化幅值大小依次为:速度极小值、平均速度、速度极大值,随着颗粒粒径增大,流经漩涡区时颗粒速度减小较大,颗粒的运动跟随性变差,颗粒在惯性力的作用下沉积在流道拐角内侧的漩涡区,由此可能造成迷宫流道堵塞。同时,以上对比分析表明,相关两相流模型和数值方法可很好预测滴头内部固液两相流动,可为滴头抗堵塞设计提供参考。
The clogging of labyrinth channel emitters is of great concern to many researchers.It is great significance to carry out the flow analysis in the labyrinth channel,to master a more comprehensive understanding of two-phase flow mechanism,and to achieve the visualization of the fluid flow and particle movement inside the labyrinth channel for the clogging of the emitters.In this paper,a high quality structured mesh is used on the basis of reference based on the ICEM CFD software.The applicability of a series of k-εturbulence models is systematically investigated and the particle movement law is further analyzed based on the Lagrangian method for discrete phase model.Compared with the experimental data cited form the literature Liming Yu et al.(2009),this paper,the various forces of single-particle were comprehensively considered,and the change law of the trajectory of single-particle with different densities and diameters were predicted,the variation of the migration velocity between single-particle and its surrounding fluid under different diameters and the variation law of the drag force of single-particle were analyzed,et al.The adaptability of 3 turbulence models(standard k-ε,RNG k-εand Realizable k-ε)in the labyrinth channel emitter were analyzed,the average errors predicted by RNG k-εand Realizable k-εmodel are 8.96%and 8.11%respectively,while the average error predicted by standard k-εmodel is only 2.32%,the standard k-εmodel is more suitable for simulating of the pure continuous-phase complex turbulent flows inside a labyrinth channel emitter.The computed trajectory characteristics of single-particle showed that the stochastic trajectory model,which considered gravity,buoyancy,virtual mass force and drag force,can be employed to capture precisely the movement of the particles in labyrinth channel.The paths of magnesium particle,sand particle and aluminum particles passing through the labyrinth channel were 43.97 mm,44.25 mm and 50.79 mm,respectively,while the paths of 65,100 and 150μm sand particle
作者
唐学林
赵旭红
李云开
李小芹
Tang Xuelin;Zhao Xuhong;Li Yunkai;Li Xiaoqin(College of Water Resources And Civil Engineering,China Agricultural University,Beijing 100083,China;Beijing Engineering Research Centre of Safety and Energy Saving Technology for Water Supply Network System,China Agricultural University,Beijing 100083,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2018年第16期120-128,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划(2017YFD0201504)
国家自然科学基金资助项目(51479196
51321001)
关键词
滴头
湍流模型
数值分析
颗粒运动轨迹
颗粒曳力
emitter
turbulence models
numerical analysis
particle moving trajectory
particle drag force
