Numerical Simulation Of Particle Sorting Based On Induced Charge Electroosmotic Flow

Continuous particle separation has great significance in many fields. In order to quickly distinguish the survival status of micro-organisms and evaluate the effect of ballast water treatment, it’s important to develop a method to sort particles based on permittivities difference. Besides, sorting impurities in lubricant based on size difference can be used for equipment maintenance and fault diagnosis.A particle sorting method was put forward in microchannel based on induced-charge electroosmotic flow (ICEOF). The principle is that the intensities of ICEOF around particles are different, hence the extents of particle-wall effect are different, and thus, different particles can be sorted. The contents and results are as following:(1) An expression of numerical solution for induced zeta potential was deduced base on the dielectric polarization theory. The expression is as following: And it was verified that the expression is applicable for dielectrics with arbitrary shape and arbitrary relative permittivity.(2)Designed the continuous particle sorting system, and the model was expounded in detail, including the governing equations, boundary conditions and initial conditions for electric field, flow field, motion of particle and method of tracking the solid-liquid interface, respectively. A series of numerical simulations were conducted, and it was demonstrated that particles in the designed channel can be sorted by relative permittivity, as well as by particle size.(3)A non-dimensional p arameter C= was defined to indicate the intensity of the interaction between the ICEOF around the particle and the channel wall. And by comparing the parameter value and the critical value, this parameter can be used to precisely predict the flow direction of particles in the designed channel.The research has some significance for the development of continuous particle sorting technology.