Abstract: In order to solve the erosive wear problem of the straight pipe section of the sonicnozzle and the main flue gas pipe caused by the discharge gas (containing dust) from the three-stage cyclone separator, the paper simulates and studies the gas-solid flow characteristics in the sonic nozzle system based on CFD technology, using the k-ε model and the DPM discrete-phase model. The two-phase flow simulation results show that by optimizing the length of the straight pipe section and the nozzle installation angle, particle-wall collision results from sub-particles (1~10 μm) can be reduced, and the jet flow can be kept away from the main flue gas pipe, which is helpful to alleviate the wear problem of the system. The research conclusions can provide direction and guidance for the engineering design and optimization of the three-cyclone degassing system.

Key words: computational fluid dynamics/CFD, sonic nozzle, two-phase flow, particle, collision