The numerical study of nanoparticle deposition in a fully developed laminar flow under different conditions is presented. The diameter of the particles ranged from 20 nm to 200 nm and the density was 1060 kg/m3. The c...The numerical study of nanoparticle deposition in a fully developed laminar flow under different conditions is presented. The diameter of the particles ranged from 20 nm to 200 nm and the density was 1060 kg/m3. The calculated results show that the small particles deposit on the wall surface more easily. More large particles deposit on the bottom wall than on the upper wall. Under the laminar conditions, the number of particles that deposit is independent of the flow velocity. The smaller the flow region is, the more the particles deposit on the wall. The longer the particles remain in the flow, the more the particles deposit on the wall, and greater the difference between the number of particles depositing on the bottom wall and the upper wall.展开更多
The vortical property in a three dimensional cavity of micro-channel flow, which is very important, was investigated numerically. The results show that the rotation direction of vortex in the cavity depends on the dim...The vortical property in a three dimensional cavity of micro-channel flow, which is very important, was investigated numerically. The results show that the rotation direction of vortex in the cavity depends on the dimension and shape of the cavity as well as the viscosity of the fluid. With the dimension and shape of the cavity fixed, there exists a critical inlet velocity. When the inlet velocity is less than the critical value, the rotation direction of vortex in the cavity will change. The critical velocity is directly proportional to the vis- cosity of the fluid, and inversely proportional to square of the thickness, length and depth of cavity. For the ratio of length and depth of cavity equals to one, there is a critical dimensionless parameter Recr , when Recr＇ is less than Recr＇ , the rotation direction of vortex will change too. Recr＇ is equal to 11.8 approximately.展开更多
基金Project supported by Major Program of the National Natural Science Foundation of China (Grant No: 10632070)
文摘The numerical study of nanoparticle deposition in a fully developed laminar flow under different conditions is presented. The diameter of the particles ranged from 20 nm to 200 nm and the density was 1060 kg/m3. The calculated results show that the small particles deposit on the wall surface more easily. More large particles deposit on the bottom wall than on the upper wall. Under the laminar conditions, the number of particles that deposit is independent of the flow velocity. The smaller the flow region is, the more the particles deposit on the wall. The longer the particles remain in the flow, the more the particles deposit on the wall, and greater the difference between the number of particles depositing on the bottom wall and the upper wall.
基金Project supported by the Natural National Science Foundation of China (Grant . No :20299030)
文摘The vortical property in a three dimensional cavity of micro-channel flow, which is very important, was investigated numerically. The results show that the rotation direction of vortex in the cavity depends on the dimension and shape of the cavity as well as the viscosity of the fluid. With the dimension and shape of the cavity fixed, there exists a critical inlet velocity. When the inlet velocity is less than the critical value, the rotation direction of vortex in the cavity will change. The critical velocity is directly proportional to the vis- cosity of the fluid, and inversely proportional to square of the thickness, length and depth of cavity. For the ratio of length and depth of cavity equals to one, there is a critical dimensionless parameter Recr , when Recr＇ is less than Recr＇ , the rotation direction of vortex will change too. Recr＇ is equal to 11.8 approximately.
