This study presents a computational fluid dynamics-based multi-flow field modelling method for an infrared hot air dryer. A three-dimensional airflow simulation of airflow in the distribution chamber was developed using a multi-stage turbulence device to optimise the uniformity of the velocity flow field. The optimised values of velocity inhomogeneity coefficient (E, maximum value), (E, average value), and velocity deviation ratio (M) decreased by 65.3%, 66.2%, and 50.9%, respectively, compared with the pre-optimisation values. Subsequently, a multi-fluid field-coupled model was developed for the drying chamber and was used to analyse the velocity, temperature, and humidity fields during the drying process. The optimised gradient-distributed turbulence plates performed better than the uniformly distributed turbulence plates. The maximum velocity difference was reduced from 0.22 to 0.1 m/s, and the temperature and humidity boundary layers on the material surface were effectively weakened, resulting in more uniform drying. Validation experiments for the optimised dryer were performed using jujube slices. The results demonstrated that the maximum deviation in drying time across the different material layers was 12.5%, and the appearance quality was uniform. The drying rates of the materials in different regions within the same drying layer were also consistent, with a maximum deviation of 5.08%. The results of this research provide technical support for future developments in equipment manufacturing and heat and mass transfer analysis of drying technology. • Developed multi-flow coupling model for flow simulation in infrared dryer chambers. • Model integrated velocity, temperature, vapor & moisture for accurate flow prediction. • Proposed and validated structural optimizations proving CFD multiphysics success in design.
Li et al. (Tue,) studied this question.