Theoretical and experimental drying of a cylindrical sample by applying hot air and infrared radiation in an inert medium fluidized bed

Drying of a cylindrical sample in a fluidized bed dryer containing inert particles was studied. For this purpose, a pilot-scaled fluidized bed dryer was constructed in which two different heat sources, hot air and infrared radiation were applied, and pieces of carrot were chosen as test samples. The heat transfer coefficient for cylindrical objects in a fluidized bed was also measured. The heat absorption coefficient for carrot was studied. The absorption coefficient can be computed by dividing the absorbed heat by the carrot to the heat absorbed for the water and black ink. In this regard, absorbed heat values by the carrot, water and black ink were used A mathematical model was proposed based on the mass and heat transfer phenomena within the drying sample. The results obtained by the proposed model were in favorable agreement with the experimental data

Common applications of thin layer drying curve equations and their evaluation criteria

In this study, thin layer drying curve equations commonly used in the literature between 2003 and 2013 are systematically discussed and evaluated in terms of their applications and selection for thin layer drying processes by considering the model evaluation criteria. As a result of this study, serious complications, confusions, and conflicts in the applications of thin layer drying curve equations and their evaluation criteria are noticed. Consequently, it is recommended that the drying curve equations should be applied in accordance with the forms commonly used in the literature. Also, it is determined that the following drying curve equations give the best results for thin layer drying processes which are the Midilli-Kucuk, Page, Logarithmic, Two-term, Wang and Singh, Approximation of diffusion, Modified Henderson and Pabis, Modified Page, Henderson and Pabis, Two-term exponential, and Verma et al. © Springer International Publishing Switzerland 2014