Development of Micro-Macro Analytical Method for Particle Impact on a Wall and Impact Charge

Abstract

Numerical simulation of impact of particles on a tubular wall in turbulent air flow has been conducted. It is found that the impact velocity normalized by the friction velocity decreased with the particle- Schmidt number. However, for larger Shmidt number, the impact velocity could not be expressed by the Schmidt number because the motion of particle depends not only on the turbulent diffusion but also on the inertia. The total impact velocity, V_total, increases with the air velocity, u₀, and can be expressed by V_total = k u₀^1.1. The result agrees qualitatively with Masda’s experimental data of the impact charge. The distribution of the total impact velocity agrees qualitatively with the experimental charge distribution.