Modeling of heat and mass transfer during ultrasound-assisted drying of a packed bed consisting of highly shrinkable material

• Published in: Chemical engineering research & design Vol. 129; pp. 25 - 33
• Main Author: Musielak, Grzegorz
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2018
• Subjects: Finite difference solution; Heat and mass transfer equations; Modelling; Numerical simulation; Shrinkage; Ultrasound-enhanced drying; Numerical simulation; Modelling; Shrinkage; Heat and mass transfer equations; Ultrasound-enhanced drying; Finite difference solution
• ISSN: 0263-8762
• DOI: 10.1016/j.cherd.2017.10.031

[Display omitted] •Mathematical model of ultrasound assisted convective drying of packed bed has been proposed.•The bed consists of highly shrinkable small grains.•The finite difference numerical method for solving the equations has been elaborated.•Numerical simulations of packed bed drying were performed for different drying conditions.•The results of simulations well reflect considered process. A new mathematical model describing mass and heat transport during ultrasound-assisted convective drying of a packed bed consisting of highly shrinkable small grains is proposed in this paper. The model assumes: linear volume shrinkage of grains, constant bed porosity, air incompressibility, small Biot number conditions of heat and mass exchange between grains and air. The model consists of four differential equations describing changes in the packed bed’s moisture content and temperature as well as in absolute humidity and temperature of the drying air passing through the packed bed. A modified Lax–Wendroff numerical method for solving the set of model equations is proposed. Numerical simulations of packed bed drying were performed for different drying conditions. The obtained results confirm both the high impact of ultrasounds on the heat and mass exchange between grains and air and small impact of ultrasound energy absorption.