多层盘式秧盘热风辅助微波干燥机优化设计与性能试验

针对现有水稻秸秆营养穴盘（简称秧盘）热风辅助微波干燥机静态干燥时存在气流场和电磁场分布不均匀、干燥效率低和干燥品质差等问题，设计了多层盘式热风辅助微波干燥机，并主要对干燥机的微波谐振腔和气流均布室进行了优化设计。利用ANSYS Electronics软件对微波谐振腔馈口不同排列方式进行仿真，根据电磁场强度均匀性及S参数的影响，确定馈口的排列方式及高度；利用ANSYS Fluent软件对气流均布室的导流腔高度、气流均布腔高度及导流体底边直径进行优化；以秧盘为试验材料对该机性能和加热均匀性进行试验验证。结果表明，优化后气流均布室出口处气体流速的均匀性指数与优化前相比提高21.26%；微波谐振腔三馈口V-L-L排列方式下电磁场强度均匀性最好且S参数最小；馈口高度为160mm时反射功率最低，比馈口高度为70mm时降低78.13%；相较于热风干燥和微波干燥，秧盘在热风辅助微波干燥方式下干燥速率分别提高291.31%和86.48%，且干燥均匀性更好。该研究可为热风辅助微波干燥机的结构优化提供参考。

Optimization Design and Performance Test of Multi-layer Tray Straw Tray Hot Air Assisted Microwave Drying Device

A multi-layer tray-type hot air-assisted microwave drying machine was designed to address the issues of non-uniform airflow and electromagnetic field distribution, low drying efficiency, and poor drying quality during static drying of existing straw-based nutrient seedling-growing bowl tray (referred to as seedling trays). The microwave resonant cavity and airflow distribution chamber of the drying machine were optimized. ANSYS Electronics software was used to simulate different arrangements of the microwave resonant cavity feed ports, based on the uniformity of electromagnetic field intensity and the influence of S-parameters, to determine the arrangement and height of the feed ports. ANSYS Fluent software was used to optimize the height of deflector chamber and height of airflow distribution chamber, as well as diameter of the bottom edge of deflector. The performance and heating uniformity of the machine were experimentally verified by using the seedling tray as the test material. The results showed that the uniformity index of gas velocity at the outlet of the optimized airflow distribution chamber was increased by 21.26% compared with that before optimization. The V-L-L arrangement of the three feed ports in the microwave resonant cavity had the best electromagnetic field intensity uniformity and the smallest S-parameters.The reflectivity was the lowest when the feed port height was 160mm, decreasing by 78.13% compared with height of 70mm. Compared with hot air drying and microwave drying, the drying rate of the seedling tray under hot air-assisted microwave drying was increased by 291.31% and 86.48%, respectively, and the drying uniformity was better. The research result can provide a reference for the structural optimization of hot air-assisted microwave drying machines.