轉輪式乾燥機使用吸附能力佳之材料作為除濕輪，並以此作為吸附劑吸收潮濕空氣中的水分。當潮濕的室內空氣進入除濕輪後，除濕輪會吸附其中的水分，因此通過除濕輪後，空氣中的水分含量較低，然而吸附劑具有吸附容量的限制，吸附一定重量的水後將失去吸附功能，此時除濕輪另一側會通過高溫且相對濕度較低的氣流，並將除濕輪中的水分帶走，使其重新回到乾燥狀態繼續吸附潮濕空氣中的水分。
然而氣流間會產生交互作用，導致溫度與水氣在不同氣流間傳遞，使原本向出口移動的乾燥氣流受到水分含量較多的氣流影響，致使乾燥效果不如預期，相對濕度較低的高溫氣流則會將熱量傳遞給乾燥後的氣流，使其溫度升高，若需要除濕的對象為熱敏感物質，則會對其造成損毀，而原本相對濕度較低的高溫氣流降溫後，飽和含水量也隨之下降，使相對濕度增加，因此對除濕輪的乾燥能力也會下降，使除濕輪中殘留較多水氣，降低除濕效率。
為了避免上述情況，本文建立乾燥機模型，對流速分佈與溫度分佈進行分析，並探討不同操作條件(如：除濕輪孔隙、孔徑、出口流速等)對流速與溫度造成的影響，研究成果將有利於未來設計乾燥機。

There will be an interaction between the airflows in air-drying machine, resulting in the transfer of temperature and moisture between different airflows. First, if water from wet air diffuses to air which is dried by desiccant wheel, drying efficiency will be less than expected. Second, heat will transfer to dry air flow from air flow with high temperature, making its temperature increases. If there is a heat-sensitive material in the room, it may be damaged by this reason. In order to have deep understanding of the above problems, this research uses the finite element method to simulate the airflow characteristics in the air-drying machine. The major of the analysis results can be summarized into the following conclusions: (1) When the porosity decreases, the velocity of the air flow will decrease, and easily flow to the outlet duct on the same side. (2) When the temperature difference between the two airflows is small, the airflow velocity will decrease, and the velocity distribution in the desiccant wheel will be relatively smooth and will not change drastically.

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