An Experimental and Computational Study of Electrostatic Fields Arising During the Pumping of Powder into Small Metal and Plastic Containers

Some experimental and computational results obtained during the study of the loading of small metal and plastic containers with electrostatically charged high-density polyethylene powder are described. The powder was charged by pneumatic transport along a polyethylene pipe, and loaded into the containers. The containers were enclosed in a Faraday cage, and the electrostatic field which built up was monitored using field mills; the mirror current to the metal container was also monitored. Measurements were taken with the metal container isolated from ground in one set of runs and earthed in another. Powder characteristics such as particle size distribution and charging tendency were also measured. A mathematical model of the experimental situation was set up, and the finite element method was used to solve the appropriate boundary value problem. Experimental and computational results are compared, and the efficacy of applying computational techniques to such problems is discussed.