Effect of Temperature on the Fluid Dynamics of Heavy Particles in a Conical Spouted Bed for Nuclear Fuel Coating

The hydrodynamic characteristics of heavy particles in a conical spouted bed at high temperatures are of critical importance for nuclear fuel coating. In this study, the effects of temperature and gas flow on the hydrodynamic behavior of heavy particles in a conical spouted bed were systematically investigated by using power spectral density (PSD). The experimental results indicate that the intensity of the main frequency peak in the annular zone decreases, while that in the spout zone gradually increases with an increasing gas flow rate at the same operating temperature. Meanwhile, the intensity and magnitude of the main frequency peak slowly decline, and the main frequency peaks broaden with the increase of temperatures at the corresponding gas flow. Based on these phenomena, the influence mechanism of temperature on the hydrodynamics of heavy particles is proposed: the large and uniform bubbles at lower temperatures evolve into the slightly small bubbles of various sizes at higher temperatures, which will increase the volume fraction of particles in the spout zone and thus improve the efficiency of spouting. This study reveals the hydrodynamic characteristics of heavy particles and provides deeper insights into spouting behaviors for nuclear fuel coating at high temperatures.