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Introduction. Current paper introduces the method for defining hydraulic losses during coolants flow in conduits and channels of heat exchangers of food production equipment. The viscosity of these coolants has a power dependency on shifting velocity. Materials and methods. The power-law fluid were taken into consideration as a special case of silicone fluids. The method for determining hydraulic developed is obtained based on the method of analogies which consists of: analyzing how local resistances and friction resistances depend on Reynolds number of Newtonian fluid; changing the real Reynolds number for Newtonian fluid to Reynolds number for power-law fluid; and thus obtaining analytical formulas. These formulas allow to define hydraulic resistances during contraction and expansion of the channel and to define local resistances during flow of power-law fluids. Results and discussion. In order to construct expressions for defining local resistances during power-law fluids flow in stepped channel and in a turn (which are the most prevalent in technological equipment) the origins of Newtonian fluid flow in channels with the same hydraulic resistance were analyzed. Using the known expressions with the aid of method of analogy, the formulas for describing the hydraulic resistance during contraction and expansion of the channel were constructed. These formulas are represented as a sum of values, which are associated with acceleration or deceleration, contraction or expansion and turning of the flow. Using the principle of analogy for different cases of Reynolds formula, the formulas for defining the local resistances of power-law fluids were obtained. Conclusion. Obtained expressions can be used to determine coefficients of local resistances during power-law fluids flow. They are equally applicable in a wide range of Reynolds number, which allows to carry out an entirely new design of technological equipment for food industry in the direction of reducing energy consumption and material cost. [ABSTRACT FROM AUTHOR]

Introduction. The problems of simulating viscoplastic longitudinal and cross-sectional flow of non-Newtonian fluids are overviewed. Materials and methods. For the first time the superposition method by expressing the components of the stress tensor for building flow fields with higher dimension from flow fields with lower dimension with various boundary conditions when rheological parameters change depending on pressure was used. The flows in the channel are categorized by velocity and pressure values in each point of the section. Results. The theoretical methods for simulating flows of non-Newtonian fluids in channels of different geometry with moving bounds and pressure drop on channel edges with respect to functional connections between main process parameters are described using the superposition method. It is shown that longitudinal and cross-sectional are reduced to the collection of one-dimensional longitudinal flows of the same type which allow to describe three-dimensional isothermal in rectangular channel and two-dimensional flows in flat channels with different channel aspect ratio. The received theoretical two- and three-dimensional model of viscous flows in channels with basic geometry allow to research main regularities of the process and to establish optimal macro-kinetic and macro-dynamic flow characteristics of non-Newtonian materials which are aimed at reducing energy costs and material consumption of food processing equipment. Conclusion. The developed and theoretically reasonable three-dimensional models flows of non-Newtonian fluids in channels allow to perform qualitatively new design of food processing equipment which allows to reduce energy costs and material consumption. [ABSTRACT FROM AUTHOR]