Study on the ultrasound-assisted drying process of deformable porous materials

Abstract

Ultrasound has been reported about very positive influence on drying efficiency of deformable porous materials such as fruits and agricultural products. Main aim of this study is a profound recognition of the enhanced mechanism of ultrasound-assisted drying of deformable porous materials by a series of simulations and experiments. Firstly, the coupled acoustic and thermo-hydro-mechanics model was solved by using Arbitrary Lagrange-Euler finite element method. Results showed that the sponge and cavitation effects led to order moisture diffusion and intensive temperature gradient in the deformable porous materials. Afterwards, the field synergy principle has been utilized for illustrating the synergistic effects induced by ultrasound. Lastly, ultrasound-induced spatial distributions of stresses and displacements in the deformable porous materials were also studied. The results suggested that the ultrasonic mechanical effects contributed to smaller deformation of the porous materials, which could effectively guarantee the sample shape and reduce volume shrinkage after drying. This study could provide scientific and historical backgrounds to the future studies concerning heat and mass transfer enhancement by ultrasound, and push the development of ultrasound-assisted drying in food engineering. • The coupled acoustic and thermal-hydro-mechanics model is established. • The enhanced mechanism of ultrasound-assisted drying has been illustrated. • Synergistic effects induced by ultrasound are investigated. • The reason why ultrasound can improve deformation of porous material is stated. • Energy flow of ultrasound-assisted drying is depicted clearly.