Study on Particle Acceleration Characteristics in Supersonic Jet Field of Fluidized Bed Opposed Jet Mill

The low energy utilization of particles in a high-speed flow field is a significant factor contributing to the inefficiency of fluidized bed opposed jet mills. To elucidate the reasons and mechanisms, this paper investigates the acceleration process of particles entrained by airflow using a combination of experimental and numerical simulations. The experimental results demonstrate that the particles are both accelerated and concentrated within the jet shear layer. Furthermore, numerical simulations indicate that turbulent kinetic energy significantly influences particle distribution within the supersonic jet flow field. The radial displacement of the particles, along with the oscillation of their acceleration direction over time and space, constitutes a key mechanical mechanism. The kinetic energy transfer between the particles and the fluid is maximized at 5.7% when the volume fraction of particles in the jet is 0.02%. These findings may offer a theoretical foundation for enhancing the grinding efficiency of fluidized bed opposed jet mill through modifications to the flow field characteristics.