In-Flight Heating Process of Cerium Oxide Powders in Radio Frequency Thermal Plasma Considering Thermal Resistance Effect

Abstract:

The in-flight heating process of cerium dioxide (CeO₂) powders was investigated through experiments and numerical simulations. In the experiment, CeO₂ powder (average size of 30 μm) was injected into radio-frequency (RF) argon plasma, and the temperatures were measured using a DPV-2000 monitor. A model combining the electromagnetism, thermal flow, and heat transfer characteristics of powder during in-flight heating in argon plasma was proposed. The melting processes of CeO₂ powders of different diameters, with and without thermal resistance effect, were investigated. Results show that the heating process of CeO₂ powder particles consists of three main stages, one of which is relevant to a dimensionless parameter known as the Biot number. When the Biot value≥0.1, thermal resistance increases significantly, especially for the larger powders. The predicted temperature of the particles at the outlet (1800–2880 K) is in good agreement with the experimental result.