SIMULATION OF HEAT AND MASS EXCHANGE PROCESS HEAT EXCHANGER OF SIDE-EVAPORATIVE TYPE

Abstract

It is known that the share of influence of the microclimate on the productivity of animals is about 20-25%. In the process of life, animals emit a large amount of heat, moisture, harmful gases, including carbon dioxide, ammonia and hydrogen sulfide. If the ventilation system does not work satisfactorily, the concentration of water vapor and harmful gases may exceed the standards, as a result of which animals drastically reduce productivity and may die. Currently, when creating livestock enterprises, it is necessary to resolve issues related to the reduction of investments, 40% of which is equipment. More than 20% of the cost of equipment falls on the heating and ventilation system; it is on it that they most often try to save money. Disagreements often arise between specialists on the deviation of microclimate parameters from optimal values for the productive qualities of farm animals. The article presents the physical and mathematical apparatus and methods for simulating the process of heat and mass transfer in an indirect-evaporative type heat exchanger for livestock buildings. The description of the process of heat and mass transfer in the heat exchanger of the indirect evaporative type of the Maisotsenko cycle is complex and requires the solution of many important mathematical problems (for example, the algorithmic solution of the combined heat and mass transfer on the surface with existing walls). Of particular importance is the development of an efficient algorithm that allows one to calculate differential equations of heat and mass transfer in partial derivatives. Therefore, the aim of the research is to describe the physical and mathematical apparatus and simulation technique (numerical simulation) of the heat and mass transfer process in an indirect evaporative type heat exchanger. As a result of analytical studies, the physico-mathematical apparatus of the process of heat and mass transfer in the heat exchanger of the indirect evaporative type of the Maisotsenko cycle was compiled, including the energy balance equation, taking into account sensitive and latent heat transfer on the surface of the wall of the wet and dry channels. The initial and limiting conditions of the heat and mass transfer model in the working part of the evaporative cooler under study are determined, which form the basis of numerical simulation in the Star CCM+ software package. A simulation technique (numerical modeling) has been developed and preliminary studies of the heat and mass transfer process in the heat exchanger of the indirect evaporative type of the Maysocenka cycle have been carried out. As a result of numerical simulation, the distributions of the temperature field, the vector field of velocities and the absolute humidity of the air flow in the heat exchanger of the indirect evaporative type of the Maysocenka cycle were obtained.