Investigation on airflow distribution under different feed thickness combined CFD modeling and experimental verification

Abstract

Belt dryer is commonly used in the production of the dried aquatic feed. Poor airflow distribution during the aquatic feed drying process leads to moisture content variation that could be lead to high energy consumption and poor feed quality. A newly designed belt dryer with improved drying efficiency was used to study airflow distribution. In order to analyze airflow distribution inside the dryer, a model for a new belt dryer was established. Airflow distribution under five different feed thicknesses (20 mm, 30 mm, 40 mm, 50 mm, 60 mm) were simulated using computational fluid dynamics (CFD) techniques and verified by experimental data. A finite volume method with porous media formulation was used to simulate airflow distribution inside the dryer. The experimental results showed that there was good consistency between the experimental and simulated values of airflow velocity. The airflow velocity on the feed layer range from 0.28 m/s to 0.98 m/s with a standard deviation of up to 0.17 m/s. Airflow distribution inside the dryer was affected by the feed thickness and air space size. When the feed thickness was 40 mm, the uniformity of the airflow velocity at the surfaces of the feed can reach the best results.