SIMULATION OF A SOLAR DRYER USING COMPUTATIONAL FLUID DYNAMICS (CFD)

Abstract

In this scientific article, the processes of heat transfer and airflow
in solar dryers were simulated using the Computational Fluid Dynamics
(CFD) method, and the possibilities of effective and high-quality drying of the
medicinal plant — Plantago major (common plantain) — were investigated.
The main purpose of the study was to optimize the solar dryer design,
increase the drying rate, and preserve product quality through the use of CFD
technologies. Using the ANSYS Fluent software, the internal temperature
distribution, airflow velocity, and temperature gradients within the drying
chamber were modeled. According to the simulation conditions, the air heated
by solar energy was maintained within the temperature range of 55–65 °C
and directed onto the product being dried. The initial moisture content of the
plantain leaves was 82%, and after 3.5–4.5 hours of drying, it decreased to
10–12%. The CFD simulation results demonstrated the following advantages:
the airflow was uniformly distributed within the dryer, ensuring equal thermal
exposure to all leaves; efficient use of thermal energy led to a reduced drying
time; the retention of biologically active compounds (flavonoids, vitamins) in
the dried product was ensured; based on CFD analysis, recommendations were
developed for improving the internal geometry of the dryer and the design of
the air inlet and outlet channels. The simulation results were compared with
experimental observations, and a high degree of agreement was recorded. The
CFD-based model significantly improved the dryer’s efficiency, enhanced drying
quality, and minimized heat losses. This study demonstrates the high potential
of CFD-based approaches for the scientific design and practical implementation
of solar dryers intended for drying medicinal plants.