High-efficiency microwave heating system for continuously processing tubular materials

Abstract

Microwave energy, as a green and clean energy source, is widely used in material processing. However, challenges like low energy conversion efficiency and poor heating uniformity often arise, particularly in thin-walled tubular materials. To address these limitations, an efficient microwave heating structure based on electromagnetic black holes (EMBH) is proposed, enhanced by the rotational motion of tubular materials for uniform processing. First, A multiphysics model is established based on electromagnetism and heat transfer in solids, and the lifting and rotating motion is further simulated according to the coordinate transformation. Second, a continuous gradient black hole structure operating at 2.45 GHz within a WR430 waveguide is designed, then realized through multi-layered dielectric and the equivalent dielectric constant method. Experimental validation demonstrates that the EMBH efficiently heats silicon carbide tubes of varying wall thicknesses, maintaining heating efficiency above 90%, while the rotating motion significantly improves heating uniformity. Furthermore, the effects of water content, tube diameter, lifting and rotating speeds, and thermal conductivity on heating performance are investigated. This proposed system offers a promising solution for the efficient and uniform continuous processing of tubular materials in industrial applications.