Three dimensional numerical modeling of simultaneous heat and moisture transfer in a moist object subjected to convective drying

The drying behavior of a moist object subjected to convective drying is analyzed numerically by solving heat and moisture transfer equations. A 3-D numerical model is developed for the prediction of transient temperature and moisture distribution in a rectangular shaped moist object during the convective drying process. The heat transfer coefficients at the surfaces of the moist object are calculated with an in-house computational fluid dynamics (CFD) code. The mass transfer coefficients are then obtained from the analogy between the thermal and concentration boundary layer. Both these transfer coefficients are used for the convective boundary conditions while solving the simultaneous heat and mass transfer governing equations for the moist object. The finite volume method (FVM) with fully implicit scheme is used for discretization of the transient heat and moisture transfer governing equations. The coupling between the CFD and simultaneous heat and moisture transfer model is assumed to be one way. The effect of velocity and temperature of the drying air on the moist object are analyzed. The optimized drying time is predicted for different air inlet velocity, temperature and moisture content. The drying rate can be increased by increasing the air flow velocity. Approximately, 40% of drying time is saved while increasing the air temperature from 313 to 353 K. The importance of the inclusion of variable surface transfer coefficients with the heat and mass transfer model is justified.

[1]  I. Dincer,et al.  Numerical Modeling of Forced-Convection Drying of Cylindrical Moist Objects , 2007 .

[2]  C. Simonson,et al.  Conduction–radiation interaction in 3D irregular enclosures using the finite volume method , 2008 .

[3]  Jose Hernández,et al.  Analytical solution of mass transfer equation considering shrinkage for modeling food-drying kinetics , 2000 .

[4]  Prabal Talukdar,et al.  An experimental data set for benchmarking 1-D, transient heat and moisture transfer models of hygroscopic building materials. Part I: Experimental facility and material property data , 2007 .

[5]  Heat and Mass Transfer Modeling of Recirculating Flows During Air Drying of Moist Objects for Various Dryer Configurations , 2007 .

[6]  J. G. Brennan,et al.  Changes in structure, density and porosity of potato during dehydration , 1995 .

[7]  Ibrahim Dincer,et al.  Two-dimensional heat and moisture transfer analysis of a cylindrical moist object subjected to drying: A finite-difference approach , 2003 .

[8]  V. K. Nema,et al.  Drying behaviour of spherical grains , 1988 .

[9]  Darko Velić,et al.  Influence of airflow velocity on kinetics of convection apple drying , 2004 .

[10]  J. G. Brennan,et al.  A Mathematical Model of Simultaneous Heat and Moisture Transfer during Drying of Potato , 1995 .

[11]  K. Cen,et al.  Experimental and Theoretical Study of Agitated Contact Drying of Sewage Sludge under Partial Vacuum Conditions , 2009 .

[12]  Antonio Mulet,et al.  Drying of shrinking cylinder-shaped bodies , 1998 .

[13]  Ibrahim Dincer,et al.  Numerical modeling of heat and mass transfer during forced convection drying of rectangular moist objects , 2006 .

[14]  Prabal Talukdar,et al.  An experimental data set for benchmarking 1-D, transient heat and moisture transfer models of hygroscopic building materials. Part II: Experimental, numerical and analytical data , 2007 .

[15]  D. R. Pangavhane,et al.  Drying behaviour of brined onion slices , 1999 .

[16]  Kankanhalli N. Seetharamu,et al.  A one dimensional analysis of convective drying of porous materials , 1996 .

[17]  A. Saha.  Three-dimensional numerical study of flow and heat transfer from a cube placed in a uniform flow , 2006 .

[18]  E. Akpinar,et al.  Evaluation of convective heat transfer coefficient of various crops in cyclone type dryer , 2005 .

[19]  W. Fernando,et al.  A model for constant temperature drying rates of case hardened slices of papaya and garlic , 2008 .

[20]  M. Hubinger,et al.  DRYING OF ONION: EFFECTS OF PRETREATMENT ON MOISTURE TRANSPORT , 1998 .

[21]  Antonio Mulet,et al.  Drying models for green peas , 1996 .

[22]  J. G. Brennan,et al.  Thermal conductivity of potato as a function of moisture content , 1992 .

[23]  W. Mcminn,et al.  Microwave Drying of Pharmaceutical Powders , 2000 .

[24]  Antonio Mulet,et al.  HEAT AND MASS TRANSFER MODEL FOR POTATO DRYING , 1994 .

[25]  Hongwei Wu,et al.  Conjugate heat and mass transfer process within porous media with dielectric cores in microwave freeze drying , 2004 .

[26]  K. Dworecki,et al.  Evolution of concentration field in a membrane system. , 2005, Journal of biochemical and biophysical methods.

[27]  A. Mujumdar.  Handbook of Industrial Drying , 2020 .

[28]  M. Perić,et al.  FINITE VOLUME METHOD FOR PREDICTION OF FLUID FLOW IN ARBITRARILY SHAPED DOMAINS WITH MOVING BOUNDARIES , 1990 .