Optimal Design of an Angular Box for a Mixed Flow Grain Dryer

Abstract

Highlights The drying effect in the drying layer is affected by the status of the flow field. The angular box of the drying oven is optimized to improve the drying effect. The structure of the variable-section angular box significantly reduced unevenness and improved the drying effect. Abstract . Dryers are subject to problems as they are unable to fully and uniformly dry grain. Considering the mixed-flow drying process and improving the drying uniformity, this study conducted a numerical simulation of the hot air temperature field, velocity field, and pressure field with ordinary equal cross-section. The dryer was optimized by a variable-section angular box structure for simulation analysis and experimental verification. The results demonstrated the following: the optimized variable cross-section angular box can improve the uniformity of the overall flow of hot air in the drying box; that is, it diffuses uniformly in the temperature, speed, and pressure field of hot air. A comparative analysis of equal cross-section and variable cross-section angled tubes indicated that the unevenness coefficient of the tubes’ wind field of the same section was reduced from 81.31% to 66.8%, 51.19% to 32.78%, and 56.98% to 42.57%, which significantly reduced unevenness and improved the drying effect. Keywords: Angular box, Flow field distribution uniformity, Grain drying, Numerical simulation.