The Basset-Boussinesq-Oseen （BBO） equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to th...The Basset-Boussinesq-Oseen （BBO） equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to the impeller rotation, as additional effects. This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid. Then based on the motion equation for particles in low Reynolds number centrifugal pumps, a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation. After that the deviations of the particle motion from the fluid motion, as predicted by the various approximations, are discussed and compared. At last, with an emphasis on the Particle Image Velocimetry （PIV） results, the tracking characteristics of particles are estimated. Also, advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.展开更多
局部遮阴情况下,光伏阵列输出的功率-电压(P-V)曲线呈多峰形式,导致传统的最大功率点跟踪(Maximun Power Point Tracking,MPPT)算法失效。为此,提出基于引力搜索算法(Gravitational Search Algorithm,GSA)的MPPT控制方法,利用粒子之间...局部遮阴情况下,光伏阵列输出的功率-电压(P-V)曲线呈多峰形式,导致传统的最大功率点跟踪(Maximun Power Point Tracking,MPPT)算法失效。为此,提出基于引力搜索算法(Gravitational Search Algorithm,GSA)的MPPT控制方法,利用粒子之间存在的相互引力,使粒子始终向质量最大的粒子移动,以指导优化搜索,实现光伏MPPT控制。在MATLAB/simulink中搭建仿真模型验证GSA算法的可行性,结果表明:相较于电导增量法和模糊控制,GSA能精准跟踪到最大功率点,避免错误跟踪导致的功率损失。展开更多
The targeted drug delivery and targeted drug therapy transport a drug directly to the center of the disease under various conditions and thereby treat it deliber- ately without effects on the body. This paper studies ...The targeted drug delivery and targeted drug therapy transport a drug directly to the center of the disease under various conditions and thereby treat it deliber- ately without effects on the body. This paper studies the magnetic drug targeting （MDT） technique by particle tracking in the presence of magnetic field in bifurcation vessels of a healthy person and a diabetes patient. The Lagrangian particle tracking is performed to estimate particle behavior under effects of imposed magnetic field gradients along the bifurcation. The results show that the magnetic field increases the volume fraction of particle in the target region, and the efficiency of MDT on a patient with the diabetes disease is better than a healthy person. Also, for the higher magnetic numbers, the flow in the upper branch is strongly affected by the magnetic field.展开更多
基金supported by the National Outstanding Young Scientist Funds of China (Grant No.50825902)the Jiangsu Provincial Innovative Scholars "Climbing" Project of China(Grant No.BK2009006)the National Natural Science Foundation of China (Grant No.50979034)
文摘The Basset-Boussinesq-Oseen （BBO） equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to the impeller rotation, as additional effects. This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid. Then based on the motion equation for particles in low Reynolds number centrifugal pumps, a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation. After that the deviations of the particle motion from the fluid motion, as predicted by the various approximations, are discussed and compared. At last, with an emphasis on the Particle Image Velocimetry （PIV） results, the tracking characteristics of particles are estimated. Also, advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.
文摘局部遮阴情况下,光伏阵列输出的功率-电压(P-V)曲线呈多峰形式,导致传统的最大功率点跟踪(Maximun Power Point Tracking,MPPT)算法失效。为此,提出基于引力搜索算法(Gravitational Search Algorithm,GSA)的MPPT控制方法,利用粒子之间存在的相互引力,使粒子始终向质量最大的粒子移动,以指导优化搜索,实现光伏MPPT控制。在MATLAB/simulink中搭建仿真模型验证GSA算法的可行性,结果表明:相较于电导增量法和模糊控制,GSA能精准跟踪到最大功率点,避免错误跟踪导致的功率损失。
文摘The targeted drug delivery and targeted drug therapy transport a drug directly to the center of the disease under various conditions and thereby treat it deliber- ately without effects on the body. This paper studies the magnetic drug targeting （MDT） technique by particle tracking in the presence of magnetic field in bifurcation vessels of a healthy person and a diabetes patient. The Lagrangian particle tracking is performed to estimate particle behavior under effects of imposed magnetic field gradients along the bifurcation. The results show that the magnetic field increases the volume fraction of particle in the target region, and the efficiency of MDT on a patient with the diabetes disease is better than a healthy person. Also, for the higher magnetic numbers, the flow in the upper branch is strongly affected by the magnetic field.
