Numerical simulation of falling film dehumidification with rectangular cylinder insertion modification at different elevations

A falling film dehumidifier is one type of desiccant-based dehumidifier with superior performance and has a simple design and working mechanism. Geometric modifications of falling film dehumidifiers can impact their fluid flow and effectiveness. For further investigations, a CFD (Computational Fluid Dynamics) numerical simulation was carried out on the dehumidifier geometric innovation equipped with a rectangular cylinder with variations in different height positions. Falling film dehumidifier with four variations of rectangular cylinder height positions (3/12 h, 5/12 h, 7/12 h, and 9/12 h) was analyzed to determine its impact on dehumidification performance for each incoming airflow of 0.5 m/s, 1 m/s, and 1.5 m/s. Based on the results, it was evident that adding a rectangular cylinder to the humid air passage can change the flow characteristics, enhance the distribution rate of mass and air temperature, and ultimately enhance the dehumidification performance. The decrease in humidity and temperature increased by 11–14% and 11–27%, respectively, for the air velocity range of 0.5–1.5 m/s. In addition, the dehumidification performance was obtained to increase by 11–14% at the same air velocity range. Variations in the position of a rectangular cylinder show different results, where the lowest position delivers the best dehumidification performance.