Effects of multi-waveguide configurations in a cylindrical resonant cavity on temperature uniformity during tire microwave vulcanization

Abstract

This study focuses on the non-uniform temperature distribution during tire microwave vulcanization and establishes a multiphysics coupled model of microwave heating in a cylindrical resonant cavity to systematically investigate the effects of waveguide arrangement, rotation angle, waveguide number, and spatial configuration on temperature-field distribution and microwave utilization efficiency. The results indicate that, for the inner-waveguide configuration, the primary heating regions are concentrated in the tread and bead areas, while variations in the number of inner waveguides have little influence on the heating region. The combined inner–outer waveguide arrangement significantly improves the temperature uniformity in the tread region, and changes in the outer-waveguide position do not alter the main heating area of the tire. For the single-waveguide structure, the 45° configuration exhibits the highest microwave utilization efficiency, with the minimum S11 value reaching −20.327 dB and the fastest heating rate. In contrast, the 90° configuration achieves the most uniform temperature distribution and the optimal heating uniformity. Compared with dual- and four-waveguide configurations, the combined three-waveguide side–upper arrangement demonstrates superior electric-field uniformity and overall heating performance, in which the rotation angle of the upper waveguide significantly affects the tire temperature distribution, and the optimal temperature uniformity is obtained at 90°. The present study systematically reveals the coupling relationship between multi-waveguide configuration parameters and tire temperature-field evolution, and provides theoretical guidance for the structural optimization and uniform microwave heating design of large and complex rubber products.