Effect of Fan Frequency on the Airflow Distribution and Moisture Content in Aquatic Feed Belt Dryer with CFD Simulation and Experimental Verification

Abstract

HighlightsCFD simulation was done for studying airflow uniformity during drying of aquatic feed in a belt dryer.The simulation predicted the airflow distribution in different feed layers of the dryer well.The fan frequency affected the moisture diffusivity and overall drying uniformity.The fan frequency of 30 Hz resulted in the best drying process.Abstract. Drying is an essential process in the production of aquatic feed products. Belt dryer is widely used in drying aquatic feed. The uniformity of airflow distribution inside the belt dryer affects the quality of dried products, the dryer efficiency, and energy consumption. Fan frequency was one of the critical factors affecting air distribution inside the dryer. However, the internal airflow distribution inside the belt dryer was not fully investigated, and air velocities were challenging to test accurately. The airflow distribution inside a belt dryer at four different fan frequencies (25, 30, 35, and 40 Hz) was studied with computational fluid dynamics (CFD) simulation and experimental verification. A finite volume method was employed to simulate airflow distribution inside the dryer. The porous medium model was added to improve result accuracy. The results showed that the simulated value of air velocity was consistent with the experimental value. The maximum gap between observed and simulated values was 7.24%, and the minimum was less than 0.1%. The air velocity on the feed layer ranged from 0.34 to 1.10 m s-1 with a standard deviation of up to 0.17 m s-1. When the fan frequency was 30 Hz, air velocity uniformity on the feed layer surfaces could reach the best results. Keywords: Airflow distribution, Belt dryer, CFD, Fan frequency, Porous media.