Solid particle size characterization by a high-frequency collision response in pneumatic particulate flow

A novel triaxial vibration method is developed for the real-time characterization of the solid particle size distribution (PSD) in pneumatic particulate flow, which is critical for chemical industry. In this work, the particle‒wall collision and friction behaviours were analysed by the time-domain statistical and time-frequency joint methods to narrow the high-frequency response range by the initial experiment of free fall for a single particle, interparticle, and multiple particles. Subsequently, verification experiments of PSD characterization in pneumatic flow were performed. First, the quantitative triaxial energy response model that considers the particle size, shape, and mass factors were established. Second, a good agreement of the particle number identification was found between the triaxial vibration energy and mean particle size of 150–550 μm. Moreover, the performance with the best accuracy was focused on a range of 42–43 kHz in the x-axis and z-axis and 36.8–38.8 kHz in the y-axis. Finally, the individual particle energy was inversely analysed by the triaxial vibration response within the optimized frequency bands, and the PSD was characterized in real-time by a low error rate, that is, 5.2% from the XZ-axis direction of sand (42–43 kHz) and 5.6% from the XYZ-axis of glass (30.9–33.9 kHz, 46.2–47.2 kHz, 38.3–41.3 kHz for each axis response). Therefore, this research complements the existing approaches for PSD characterization in particulate multiphase flow.