No abstract

Резюме. Цель. Целью исследования является моделирование теплофизических процес-сов, происходящих при проведении тепловых лечебных процедур на стопу с использованием технического средства, в котором в качестве источника тепла и холода выступает термо-электрическая батарея (ТЭБКлючевые слова : термоэлектрическое устройство, стопа, теплопередача, охлажде-ние, нагрев, модель, численный эксперимент

Objectives The aim of the study is to consider the design of a device for the cautery of bleeding by the method of local freezing of the blood flow zone performed using a salt with a low cryohydrate dissolution temperature, as well as to model heat exchange processes when using this technique.MethodA design for a device for cauterising bleeding using salts having a low dissolution temperature was developed. This ensures a high cooling intensity, shortening the time of formation of a thrombus stopping the blood flow. A model of the device was constructedaccording to the principlesgoverning the solidification of a viscous liquid and heat transfer associated with the dissolution of salts in water. The model was calculated using the finite difference method. A determination of haemostasis duration wasprovided by a numerical experiment.ResultsPlots of the temperature dependence of the salt solution in water over time are obtained, reflecting the duration of the device's output to operating mode, as well as plots of duration of a 3 mm thick formation of solid phase blood against the temperature of the solution for different values of blood flow pressure in the wound area.Conclusion On the basis of the numerical experiment, it was established that ammonium nitrate can be used as a working substance (salt) in the device. When it is dissolved in water, the minimum temperature of the solution is 256 K. The selection of the salt type and its quantity should be guided by medical norms and regulations in order to avoid the process of frostbite of the tissues adjacent to the bleeding zone. It was shown that the duration of blood solidification and the formation of a thrombus of the required thickness depend significantly on the pressure of the blood flow in the wound area, which must be taken into account when designing the device.

The paper presents the construction of thermoelectric augmenter of heat transfer. The construction uses the constrained blow of air current in the corresponding gaps by means of air moving unit with the objective to increase the coefficient of heat-exchange between thermoelectric junctions and the media moving in transport areas. The paper considers the device model built on the basis of solving the equations of thermal balance along the media flows in transport areas, thermoelectric battery surface, gaps between transport areas and battery surface for the straight flow. The theoretical research of heat transfer augmenter was carried out by means of the developed model.

Objectives In this research, we aimed to develop a thermoelectric device (TED) for intracavitary hypothermia, to carry out experimental studies into its functional characteristics, as well as to develop treatment procedures using this device.Method A TED design for intracavitary hypothermia was developed, consisting of two thermoelectric batteries (TEBs) interconnected using an allmetal heat pipeline equipped with an influencing applicator and a liquid heat exchanger. Experimental studies of the device were carried out on a designed bench, which included a climatic chamber, a source of electrical energy and a temperature meter connected to a PC. Results Temperature changes at the control points of the device were recorded over time. Changes in the time taken to stabilise temperatures of the device tip, heat pipe and heat sink system at different TEB supply currents were investigated. Possible methods for treating some ENT diseases using the developed device are described.Conclusion It is shown that the temperature of the applicator is stabilised after approximately 4-4.5 minutes without load. At the same time, an increase in the current of the additional TEB from 5 to 12 A at the main TEB current of 23 A reduces the temperature from 237 K to 224 K. In the process of carrying out the procedures, the necessary level of a decrease in the temperature of a biological object can be reached at the supply current of the main and additional TEBs equal to 23 and 12 A, respectively, after 2.5 minutes. The full potential of the TED device will be realised through the developed of methods for treating ENT diseases.