As a major configuration of membrane elements,multi-channel porous inorganic membrane tubes were studied by means of theoretical analysis and simulation.Configuration optimization of a cylindrical 37-channel porous in...As a major configuration of membrane elements,multi-channel porous inorganic membrane tubes were studied by means of theoretical analysis and simulation.Configuration optimization of a cylindrical 37-channel porous inorganic membrane tube was studied by increasing membrane filtration area and increasing permeation efficiency of inner channels.An optimal ratio of the channel diameter to the inter-channel distance was proposed so as to increase the total membrane filtration area of the membrane tube.The three-dimensional computational fluid dynamics(CFD) simulation was conducted to study the cross-flow permeation flow of pure water in the 37-channel ceramic membrane tube.A model combining Navier–Stokes equation with Darcy's law and the porous jump boundary conditions was applied.The relationship between permeation efficiency and channel locations,and the method for increasing the permeation efficiency of inner channels were proposed.Some novel multichannel membrane configurations with more permeate side channels were put forward and evaluated.展开更多
Particulate matter （PM） has received considerable attention from scientists because of its adverse effects on human health. Unmanned aerial vehicles （UAVs） offer a new approach for monitoring PM in inaccessi- ble ...Particulate matter （PM） has received considerable attention from scientists because of its adverse effects on human health. Unmanned aerial vehicles （UAVs） offer a new approach for monitoring PM in inaccessi- ble or dangerous locations. Computational fluid dynamics software and a wind-tunnel experiment were used to evaluate the flow field at 20, 30, and 40m/s, as well as the trajectories of PM1, PM2.5, and PMlo. The numerical simulation results show that the PM sampling head can be installed 440-680 mm from the UAV nose, and at least 130, 135, and 145 mm below the horizontal axis for free stream velocities of 20, 30, and 40 m/s, respectively. Wind-tunnel experiment results confirmed and improved on those numer- ical results, and showed that the PM sampling head can be 500-600 mm aft the UAV nose, at vertical distances below the horizontal axis of at least 138 mm for 500-550 mm, and 157 mm for 550-600 mm. In addition, sampling points can be located at either side of the optimal ranges, not only on the center line or the UAV.展开更多
基金Supported by the National Basic Research Program of China(2012CB224806)the National Natural Science Foundation of China(21490584,21476236)the National High Technology Research and Development Program of China(2012AA03A606)
文摘As a major configuration of membrane elements,multi-channel porous inorganic membrane tubes were studied by means of theoretical analysis and simulation.Configuration optimization of a cylindrical 37-channel porous inorganic membrane tube was studied by increasing membrane filtration area and increasing permeation efficiency of inner channels.An optimal ratio of the channel diameter to the inter-channel distance was proposed so as to increase the total membrane filtration area of the membrane tube.The three-dimensional computational fluid dynamics(CFD) simulation was conducted to study the cross-flow permeation flow of pure water in the 37-channel ceramic membrane tube.A model combining Navier–Stokes equation with Darcy's law and the porous jump boundary conditions was applied.The relationship between permeation efficiency and channel locations,and the method for increasing the permeation efficiency of inner channels were proposed.Some novel multichannel membrane configurations with more permeate side channels were put forward and evaluated.
文摘Particulate matter （PM） has received considerable attention from scientists because of its adverse effects on human health. Unmanned aerial vehicles （UAVs） offer a new approach for monitoring PM in inaccessi- ble or dangerous locations. Computational fluid dynamics software and a wind-tunnel experiment were used to evaluate the flow field at 20, 30, and 40m/s, as well as the trajectories of PM1, PM2.5, and PMlo. The numerical simulation results show that the PM sampling head can be installed 440-680 mm from the UAV nose, and at least 130, 135, and 145 mm below the horizontal axis for free stream velocities of 20, 30, and 40 m/s, respectively. Wind-tunnel experiment results confirmed and improved on those numer- ical results, and showed that the PM sampling head can be 500-600 mm aft the UAV nose, at vertical distances below the horizontal axis of at least 138 mm for 500-550 mm, and 157 mm for 550-600 mm. In addition, sampling points can be located at either side of the optimal ranges, not only on the center line or the UAV.
