An Investigation On Modeling Of The Particle-wall Interactions In Electrokinetic Flow

Particles have been the fundamental research object in gas-solid multiphase flow. For more precise understanding of gas-solid multiphase flow, a systematic study of the movements of particles in the fluid is necessary.This paper focus on the theoretical computation, numerical simulation and experimental research on modeling of particle-wall interactions in electrokinetic flow. Main research effort and results are as follows:(1) In this paper, the flow field, electric field, temperature distribution and concentration distribution in electrokinetic flow are described, respectively, with multi-physics governing equations. Systematic analysis is carried out on the process of particles collision and coagulation. Expressions of van der Waals force, the elastic deformation force, gravity and wall repulsion are obtained. Solving method of particle collision efficiency is achieved through Maxwell velocity distribution.(2) Based on the electrokinetic flow theory, numerical simulation research is carried out on conductive particles with different shapes in micro straight channels, through C-Language programming describing governing equations of electric field, flow field, concentration distribution and boundary conditions of induced electric percolation in the User Defined Function(UDF) interface in Fluent.(3) The visualized test bench based on the Micro-PIV technique is established. The experimental investigation of particle-wall interactions in electrokinetic flow is carried out. Based on the electrokinetic flow theory, a micro straight channel chip embedded with circular conductive particles is designed. The flow pattern around the conductive particles in the 50 V DC electrokinetic flow is studied. Experimental results partially verified the numerical simulation results and provided a basis for subsequent experiments.(4) Based on the particle-wall collision model, the relations between the collision angle and the particle initial velocity during compression stage, as well as the compression distance when speed reduce to zero during rebound stage, with the maximum compression distance, through theoretical calculation. The collision efficiency of particle-wall collisions is further obtained.