Development of conjugate heat- and moisture-transfer model for pineapple drying using OpenFOAM

Abstract

The kinetic model of drying is important for food preservation, particularly for pineapples, which have a high moisture content and are highly perishable. This paper presents a novel approach utilizing OpenFOAM, which is an open-source computational fluid dynamics (CFD) software, to model the hot-air drying kinetics of pineapple slices. The developed conjugate heat- and moisture-transfer model integrates forced-convection phenomena with moisture-diffusion dynamics. Owing to enhancements to the original OpenFOAM solver, C++ programming facilitates the appropriate representation of heat and moisture transfer based on the finite-volume method. Experimental data are utilized to derive a moisture diffusivity model, which achieved high statistical quality with an average R2 of 0.9443. Additionally, the SST k–ω turbulence model accurately describes the airflow around the pineapple-slice model. The developed model agrees well with the experimental results, with an average error of less than 1.29 %. Further analysis using the model provides insights into the effects of variations in the pineapple-slice geometry, where increased inner diameter and reduced thickness result in enhancement indices of 1.002 and 1.005, respectively. This novel CFD solver is promising for simulating the drying processes of various agricultural products, including pineapples, thus contributing to improvements in process optimization and efficiency.