Development of mathematical model of black currant berries drying process in vacuum device with the microwave power supply

The mathematical model of black currant berries drying process in vacuum device with the microwave power supply, differing in high space and temporary specification is developed, the structure of separate berries and a layer of berries is considered, heat- and physical parameters depend on coordinate and time as well as in the accounting of berries form change and a berries layer structure in the dehydration process. We used the particles dynamics method for modeling of mechanical behavior of berries which is increasingly being used now in different branches of science and technology. To give the model the high space specification the modeled berries layer consists of 20-50 separate berries, each berry depending on diameter being broken into approximately 100 separate elements. Berries elements are divided into 3 types depending on the physical properties (peel, pulp, seeds). Therefore, in general, from the point of space detail, a layer of berries consists of 2000-5000 elements. Modeling is carried out in two-dimensional Cartesian space X-Z. The condition of each element of circle is set by four variables: Cartesian coordinates of its center and two components of speed. Mechanical interaction of elements among themselves is accepted to be viscous and elastic that allows to consider the main mechanical properties of berries - the elasticity module, internal friction index. Within the developed model it is considered that between the neighbor elements there can be pushing away forces (at the introduction of elements into each other), or attractions (at a distance of the linked elements from each other). The description of the processes of warm and moisture exchange between the elements as well as between the elements and environment is based upon the standard equations of drying. In model it is considered that the microwave power brought is redistributed in the heated volume in proportion to elements moisture.