Jiayuan Zhang

Pseudo-particle simulation of multi-scale heterogeneity in fluidization

Fluidization is a process of wide application, but its dynamic behavior is not well understood because of its multi-scale heterogeneity and regime multiplicity which are difficult to simulate in traditional numerical methods. By discretizing the fluid phase into a large number of interactive simple particles, which can incorporate many-body moving boundaries easily, pseudo-particle modeling (PPM) has reproduced reasonable radial and axial heterogeneity on macro-scale as well as solids clustering and fluid flows on meso-and micro-scales. The simulation suggests a consistent evolution of the complexity across different scales with itself serving as an ideal exploring tool.

Simple measurement of restitution coefficient of irregular particles

Abstract Restitution is an important physical and mechanical property of granular materials. However, measuring its values in instantaneous collisions between particles is very difficult, especially for ore particles of irregular shapes. In this paper, restitution is measured indirectly and statistically with two cameras recording from different angles the trajectories of the ore particles rebounding from a steel plate. The momenta of the particles prior to and after the collision are calculated from the trajectories to give the restitutions of these collisions. The restitution between ore particles is then derived from the restitution of a steel ball with the steel plate measured in the same way. The approach has been proved to be practical and reliable for a variety of ore particles with moderate restitutions.

Research collaboration group on multi-scale methodology and complex systems

Background In response to the evolution of science and technology from compartmentalization to reunification, the study of complex systems and multi-scale methodology has received increasing attention from various scientific disciplines and engineering fields, so much so that complexity has sometimes been called the science of the 21st century with multi-scale methodology as an accompanying challenge.