Study on the Fixation of Mulberry Leaf Tea in a Multiport Microwave System

Abstract

Microwaves have the advantages of faster heating speed, shorter fixation time, and less pollution in tea fixation. However, there are few studies on the microwave fixation of mulberry leaf tea, which is not conducive to the promotion of mulberry leaf tea production. In order to study the fixation of mulberry leaf tea, the coaxial probe method is used to measure the dielectric constant of mulberry leaves, and the relationship connecting the real and imaginary parts of the dielectric constant and the moisture content is obtained through fitting. Based on this, a multiphysics model for mulberry leaf fixation in a six-port microwave cavity is established, which combines the characteristics of mulberry leaves, multiport heating, and mobile heating techniques. The impact of some important parameters, such as the layout and position of input ports and the thickness of mulberry leaves on the fixation process, are studied. The results show that the mutual energy coupling between ports can be reduced by using the noncoherent polarization of electromagnetic waves when the position of the ports in their working planes and the thickness of the mulberry leaves are set to (−0. 14 m, −0.15 m), (0.25 m, −0.15 m), (0.25 m, 0.15 m), (0.14 m, 0.15 m), (0.11 m, 0.0 m), (0.25 m, 0.15 m), (−0.14 m, 0.15 m), (0.11 m, 0.0 m), (0.11 m, 0.0 m), and 0.015 m when good fixation of mulberry leaves can be obtained. The study established a continuous microwave fixation experimental system for mulberry leaf tea. The experimental results indicate that the thickness of the tea affects its temperature uniformity in the microwave fixation system, which in turn affects the final quality of the tea. This study provides a reference for the industrialization of the microwave fixation of mulberry leaf tea.