考虑热阻效应下的氧化铈粉末在射频热等离子体中的飞行加热过程

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

摘要:

对二氧化铈（CeO₂）粉体的飞行加热过程进行了实验和数值模拟研究。在实验中，将CeO₂粉末（平均粒径30 μm）注入射频氩等离子体中，并使用DPV-2000监测仪测量温度。此外，提出了一种结合氩气等离子体中粉末飞行加热的电磁、热流和传热模型。研究了不同粒径的CeO₂粉体的熔化过程以及在热阻作用下的熔融过程。结果表明，CeO₂粉末颗粒的加热过程包括3个主要阶段，其中一个阶段与一个称为Biot数的无量纲参数有关。当Biot数≥0.1时，热阻显著增大，尤其对于较大的粉体。预测的颗粒出口温度（1800~2880 K）与实验结果吻合较好。

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.