Estudo experimental para a obtenção do coeficiente de transferência de calor por ebulição em um termossifão de vidro

Abstract

Thermosyphons are widely used to aid in obtaining thermal energy not only in industrial systems, but also in domestic equipment, such as: solar collectors for domestic water heating. Its main advantage is to work with the phase change of the working fluid, causing the heat transfer rate to be increased and due to this fact, these components are more compact and more efficient when compared with conventional heat pipes. In the design of systems that use this technology, the main parameter to be determined, being the basis of the design of the rest of the equipment, is the coefficient of biphase heat transfer inside the evaporator. This coefficient changes while the characteristics of the internal flow to the tube change, so for the accomplishment of this work a bibliographical review of the boiling regimes and of the existing correlations up to the present moment was made. In addition, experiments were carried out on a bench containing a glass thermosyphon, using water as working fluid and an electric resistor as a source of energy in the form of heat. The power in the tape was varied from 60 to 100 W and then the bench data were compared with the theory and the analysis showed that none of the correlations used in the present work approached the results obtained experimentally.