The variable nature of Biot numbers in food drying

A new solution approach for simultaneous heat and mass transfer during convective drying of mango

“…In order to relate internal and external resistances to mass or heat fluxes, introducing Biot numbers (Bi) is essential. These dimensionless variables are useful to identify controlling mechanisms (Giner et al, 2010). Heat and mass transfer controlled mechanisms can be deduced directly from differential transfer equations if they are rewritten in terms of dimensionless variables.…”

Comments on “The variable nature of Biot numbers in food drying” by S.A. Giner, R.M.T. Irigoyen, S. Cicuttín, and C. Fiorentini [Journal of Food Engineering 101 (2010) 214–222]

“…Giner et al (2010) introduced the following identity during the development of Eq. (3) in order to obtain the Bi m definition appearing in Eq.…”

“…Despite the meaningless nature of the term op v /or, a comparison between the corrected mass Biot number and the one proposed by Giner et al (2010) will be developed in order to remark its effect on the analysis of the drying process. Eqs.…”

“…A straight consequence of these results is that the Bi m number defined in the way given by Giner et al (2010) cannot be directly used to establish a controlling mechanism during drying processes in the same way as a Bi W m number appearing in a boundary condition of the form of Eq. (8).…”

“…(8). The numerical relationship Bi W m =Bi m can be easily calculated at the beginning of the wheat drying process described by Giner et al (2010) as follows:…”