Numerical Investigation of Force Network Evolution in a Moving Bed Air Reactor

Abstract

In spite of extensive research on macroscopic solid movements in the dense granular system of a moving bed air reactor, research on the evolution characteristics of the mesoscale inter-particle contact force network is still lacking. In this work, discrete element simulations are conducted to investigate the force chain structure properties in a moving bed air reactor. The results show that during the particle discharging process, the force chain network exhibits great anisotropy, and force chain contacts account for only about 13–14% of all inter-particle contacts, while the strong particle–particle contacts account for about 37–41% of all the particle–particle interactions. The collimation coefficients of force chains are more stable at the early stages and then decrease sharply over time. Both particle–particle and particle–wall friction coefficients affect the number, strength, collimation coefficient, and direction of force chains but have little influence on the length distribution of force chains. An in-depth analysis of the evolution of the force network provides new insights for further understanding dense granular flow in a moving bed air reactor for chemical looping combustion.

Keywords

• force network
• discrete element method
• dense granular system
• moving bed