Direct numerical simulation of motion of rigid particle in a deterministic lateral displacement device

YU Wenguang, YU Zhaosheng, YE Shangjun, SHAO Xueming, WANG Bokang

(Department of Mechanics, Zhejiang University, Hangzhou 310027, China)

Abstract: In order to solve the problems of the accuracy of numerical simulation of deterministic lateral displacement(DLD) device and study of particle separation, a direct numerical simulation method (i.e. fictitious domain method) was used to simulate the motion of rigid particle in DLD. After the analyzing the effects of lateral boundary condition, the relationship of internal flow field tilt angle and boundary conditions were established. The periodic boundary conditions were presented to simulate DLD with a huge number of lateral arrays. The numerical method and boundary condition were evaluated on a characteristic of the internal flow field and the separation diameter. The critical diameter of a rigid particle in DLD was tested. The experimental results show that for the practical DLD devices with a huge number of lateral arrays, the periodic boundary condition with fewer arrays can be adopted to reduce the computational cost.

Key words: deterministic lateral displacement(DLD); fictitious domain method; particle separation; critical particle diameter