Numerical modeling of convective drying of food with spatially dependent transfer coefficient in a turbulent flow field

• Published in: International journal of thermal sciences 2014-04, Vol.78 (78), p.145-157
• Main Authors: Ateeque, Md, Udayraj, Mishra, Ranjeet K., Chandramohan, V.P., Talukdar, Prabal
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Computational fluid dynamics; Convective drying; Drying; Evaporation; Fluid flow; Food drying; Food engineering; Food industries; Foods; Fundamental and applied biological sciences. Psychology; General aspects; Heat and mass transfer coefficients; Mass transfer; Mathematical models; Matlab; Simultaneous heat and mass transfer; Turbulent flow
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2013.12.003

A numerical model is developed for prediction of transient moisture content of food materials. The moisture transfer is modeled considering diffusion of liquid water from inner layer to outer surface of the food material followed by evaporation of water from the surface to the dry air which flows over the moist food material. Discretization of transient heat and mass transfer governing equations are done using the finite-volume method (FVM). A 3-D code in MATLAB is developed to solve the simultaneous heat and mass transfer equations. The flow field over the moist food material is assumed to be turbulent and SST k–ω turbulence model is used for prediction of heat transfer coefficient using a computational fluid dynamics (CFD) commercial code. The sample moist food material is considered to be a rectangular shaped potato and the effects of temperature and velocity on drying behavior of the same are predicted. Different drying rate periods are identified. The numerical model is validated with experimental data with a reasonable agreement. •Three dimensional numerical model for predicting transient moisture content.•SST k–ω turbulence model estimates better value of surface transfer coefficient.•Consideration of surface evaporation and face dependent surface transfer coefficient.•For low velocities, constant drying rate period can be found.•For higher velocities, three falling rate periods are observed.