Temperature and moisture distribution of cranberry during convective drying: a simultaneous heat and mass transfer solution

A 2D numerical solution was developed to estimate the temperature and moisture distribution of a spherical moist product. The object used in the study is cranberry (Vaccinium macrocarpon). Robin boundary condition was incorporated as the heat and mass transfer takes place from the object by convection. The governing transient partial differential equations were discretized by the finite difference method. The transient terms were discretized using an implicit scheme. A computer program was generated to solve the heat and moisture transport expressions simultaneously. The diffusion coefficient was assumed as temperature dependent which allowed solving of the heat and moisture transport expressions simultaneously. Temperature and moisture profiles were calculated at various drying times and hot air temperatures ranged from 313 to 348 K. Mean and center temperature and moisture content were calculated. The average moisture content was reduced from 7.49 to 2.58, 0.65 and 0.24 kg (kg of db)−1 at drying time of 10 h and hot air temperatures of 313, 333 and 348 K, respectively. The product needed to be dried up to 2, 3 and 5.5 h at drying temperature of 348 K to maintain 50%, 30% and 10% of its initial moisture content. The results obtained were compared to existing work, and it was in good agreement.