This paper presents a mathematical model and numerical analysis of the convective drying process of small particles of potatoes slowly moving through the flow of a drying agent - hot moist air. The drying process was analyzed in the form of a one-dimensional thin layer. The mathematical model of the drying process is a system of two ordinary nonlinear differential equations with constant coefficients and an equation with a transcendent character. The appropriate boundary conditions of the mathematical model were given. The presented model is suitable in the automated control. The presented system of differential equations was solved numerically. The analysis presented here and the obtained results could be useful in predicting the drying kinetics of potatoes and similar natural products in a conveyor-belt dryer. [Projekat Ministarstva nauke Republike, br. TR-33049, br. TR-37002 i br. TR-37008]

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This paper presents the mathematical model and numerical analysis of the convective drying process of thick slices of colloidal capillary-porous materials slowly moving through conveyor-belt dryer. A flow of hot moist air was used as drying agent. The drying process has been analyzed in the form of a 2-D mathematical model, in two directions: along the conveyor and perpendicular on it. The mathematical model consists of two non-linear differential equations and one equation with a transcendent character and it is based on the mathematical model developed for drying process in a form of a 1-D thin layer. The appropriate boundary conditions were introduced. The presented model is suitable for the automated control of conveyor-belt dryers. The obtained results with analysis could be useful in predicting the drying kinetics of potato slices and similar natural products.

A method of planning and designing product sorting systems in warehousing is described. The theoretical background of the analytical models and simulation modelling is given. A calculation of the capacity of elements forjoining and dividing for different priorities of material flow is described. New parameters are introduced in the formula for calculating the average number of unit loads in a system for joining, in the direction of the slave flow and for a simple analytical model for joining material flows with two different priorities with an exponential distribution of inter-arrival time. Simulation results are obtained using the GPSS/FON simulation language. Some characteristic results, used in the process of planning and design of two new distribution centres in Belgrade, are shown.

In this paper an analysis of the influence of parameters of flights from inner drying chamber structure and drying chamber is given. The influence of the following parameters on dryer working process is analyzed: number, shape and width of flights, level of coverage of cross-section drying chamber by material, rpm and drying chamber diameter. In the analytical expression for determining the amount of material seized by a curved flight, depending on the current position of the flight during drum rotation, a new parameter is introduced, compared to expression for a rectilinear flight. The expanded analytical expression could be used for optimization