The sedimentation of cylindrical pollutant particles which fall through a fluid is investigated. Differing from previous research work, particle oscillation and effect of particle on the fluid are considered, and the ...The sedimentation of cylindrical pollutant particles which fall through a fluid is investigated. Differing from previous research work, particle oscillation and effect of particle on the fluid are considered, and the torque exerted on a particle when viscous fluid flow around a particle is got through experiment and included in the numerical simulation. The computational results showed that the sedimentation velocities of particle increase slowly with the increase of particle aspect ratio . For disk like particle, when the motion direction of particle is parallel to axis of particle, particle falls more slowly than the case of perpendicular to axis of particle; while for rod like particle, it is inverse. For sedimentation of a crowd of high frequency oscillating cylindrical particles with arbitrary initial orientation, both vertical velocity and horizontal velocity oscillate dramatically, the degree of oscillation of the former is stronger than the later. A crowd of particles fall more quickly than an isolated particle. Particles tend to strongly align in the direction of gravity. The computational results agreed well with the experimental ones and helpful for controlling of pollutant particles.展开更多
The diffusion-based micro flow of a T-sensor with three inlets in whichvarious species are injected was simulated numerically. The results show that the Reynolds number isan important factor of affecting the efficienc...The diffusion-based micro flow of a T-sensor with three inlets in whichvarious species are injected was simulated numerically. The results show that the Reynolds number isan important factor of affecting the efficiency of diffusion. The smaller the channel width is, themore strongly the species diffuse. The velocity gradient across the channel width plays a key rolein the diffusion of species. The conclusions are helpful to the design of micro-fluidic devices andthe analysis of data collected from such devices.展开更多
The study of cylindrical particulate flows has wide industrial applicability and hence received much attention. The purpose of the present paper is to provide a review on the motion of cylindrical particles in shear l...The study of cylindrical particulate flows has wide industrial applicability and hence received much attention. The purpose of the present paper is to provide a review on the motion of cylindrical particles in shear layer, converging channel and jet flows, the dynamic of cylindrical particles sedimentation in a Newtonian fluid, the characterization of turbulent cylindrical particulate flows, the property of interaction between the particles, the structural feature and rheology of suspensions, the analysis of hydrodynamic instability of cylindrical particle suspensions. Finally, the concluding remarks are given.展开更多
基金TheNationalNaturalSciencesFoundationforOutstandingYouthofChina (No .1 992 52 1 0 )
文摘The sedimentation of cylindrical pollutant particles which fall through a fluid is investigated. Differing from previous research work, particle oscillation and effect of particle on the fluid are considered, and the torque exerted on a particle when viscous fluid flow around a particle is got through experiment and included in the numerical simulation. The computational results showed that the sedimentation velocities of particle increase slowly with the increase of particle aspect ratio . For disk like particle, when the motion direction of particle is parallel to axis of particle, particle falls more slowly than the case of perpendicular to axis of particle; while for rod like particle, it is inverse. For sedimentation of a crowd of high frequency oscillating cylindrical particles with arbitrary initial orientation, both vertical velocity and horizontal velocity oscillate dramatically, the degree of oscillation of the former is stronger than the later. A crowd of particles fall more quickly than an isolated particle. Particles tend to strongly align in the direction of gravity. The computational results agreed well with the experimental ones and helpful for controlling of pollutant particles.
文摘The diffusion-based micro flow of a T-sensor with three inlets in whichvarious species are injected was simulated numerically. The results show that the Reynolds number isan important factor of affecting the efficiency of diffusion. The smaller the channel width is, themore strongly the species diffuse. The velocity gradient across the channel width plays a key rolein the diffusion of species. The conclusions are helpful to the design of micro-fluidic devices andthe analysis of data collected from such devices.
基金*Project supported by the National Natural Science Foundation of China (Grant No: 10372090).
文摘The study of cylindrical particulate flows has wide industrial applicability and hence received much attention. The purpose of the present paper is to provide a review on the motion of cylindrical particles in shear layer, converging channel and jet flows, the dynamic of cylindrical particles sedimentation in a Newtonian fluid, the characterization of turbulent cylindrical particulate flows, the property of interaction between the particles, the structural feature and rheology of suspensions, the analysis of hydrodynamic instability of cylindrical particle suspensions. Finally, the concluding remarks are given.
