RESULTS OF SIMPLIFIED MATHEMATICAL MODELING OF LIQUID TEMPERATURE DISTRIBUTION IN THE HEAT EXCHANGE CHANNEL OF AN ELECTRIC HEATER WITH AN INTERNAL HEAT SOURCE
Indirect electrical resistance heating systems are heaters with internal heat sources and are widely used in agriculture for heating gaseous and liquid media. Such systems are characterized by insufficient intensity of heat exchange processes. This implies a large heat transfer surface area and significant geometric size. Earlier, an attempt was made to solve the problem of increasing the efficiency of heat transfer processes and minimizing the geometric size of the heat exchanger. For this purpose, the heat exchange characteristics were simulated and the geometric dimensions of three heat exchange systems were determined: “pipe with internal heat sources in a dielectric pipe”, “pipe with an internal heat source - a membrane of heated liquid” and “cylindrical coil - heated liquid”. The analysis of these heat exchange systems has shown that the most promising is a coil-type heat exchanger. This system has the best heat transfer characteristics and the most compact size. To confirm the correctness of the applied method of calculating the heat exchange and geometric parameters of the heat exchanger, the simulation of the temperature distribution of the heated liquid in the channel of the coil heat exchanger is implemented in this work. The verification calculations carried out under the formulated assumptions, using the example of a coil heat exchanger, show that the method for determining the heat exchange and geometric parameters of heat exchangers is correct. As a result of the simulation, it has been found that the error in determining the required channel length of the coil heat exchanger, the number of turns and the height of the coil to reach the liquid temperature at the outlet of 75°C does not exceed 4%. A similar conclusion can be made regarding the heat exchangers of the types “pipe with internal heat sources - heated liquid” and “pipe with an internal heat source - a membrane of heated liquid”.