Numerical simulation of the velocity and stress fields for a flowing powder using the smoothed particle method and experimental verification

Numerical simulation of the velocity and stress fields for a flowing powder which consists of uncountablly numerous particles is one of the most difficult problems in powder technology. We have numerically simulated these fields of flowing powder using the smoothed particle (SP) method based on the relationships of the stress-strain rates obtained by the Distinct Element Method. In the SP method, the partial differential equations, which are the governing equations of the flow fields, are transformed to ordinary differential equations, which are Lagrangian-type equations of particle motions. The numerical analysis of ordinary differential equations is much easier than that of partial differential equations. Moreover, Lagrangian analysis is suitable for the description of the characteristics of discrete particles. The calculated results of the velocity and stress fields in a two-dimensional rectangular hopper are compared with the measured values obtained under nearly the same conditions, and a fairly good agreement among them is obtained. These results show that the SP method is an effective tool to simulate the various flow fields of powders which consist of uncountablly numerous particles.