Computational Fluid Dynamics (CFD) Analysis of a Solar Dryer with Backup Incinerator

Abstract

Experimental investigations have been conducted to improve agricultural products'
drying rate through solar dryers. Computational Fluid Dynamics (CFD) has emerged
as a powerful tool for optimizing design. Drying in enclosed spaces with vents has
been employed to mitigate the challenges associated with open sun drying, including
contamination by dirt, pests, and rodents. This study focuses on the design and
experimental evaluation of a solar dryer with a backup incinerator for drying selected
farm produce. The dryer's performance was also modeled and simulated using CFD
to analyze temperature distribution under varying wind velocities. A 3D model of the
solar flat plate collector was developed using ANSYS Workbench (3D, pressure-based,
standard k-epsilon), and meshing was created in ANSYS ICEM, consisting of
95,715 nodes and 522,760 elements. Results from ANSYS FLUENT revealed that the
temperature during solar drying is directly proportional to solar radiation, with a
maximum collector temperature of 76°C at the absorber plate and 59°C on the drying
trays at an air velocity of 3.5 m/s. Experimental validation showed CFD results to be
higher due to material property variations. During incinerator-assisted drying, a
uniform temperature of 45°C was observed with forced convection. This setup is
viable for crop drying during cloudy weather and at night.