Experimental investigation of the thermal performance of screen mesh wick heat pipes operating in mid-level temperature

• Autor(a) principal: Débora de Oliveira Silva
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações do INPE
• Texto Completo: http://urlib.net/sid.inpe.br/mtc-m21c/2018/08.21.18.18

Heat pipes are two-phase heat transfer devices with the capacity of transfer large amounts of heat with a small temperature difference between the evaporation section and the condensation section, making the heat transfer process be highly efficient. The robust and simple tubular structure with no moving parts makes the heat pipe a perfect choice for different applications such as industrial or aerospace sector. Heat pipe technology has been widely applied in various areas, such as heat exchangers, spacecraft thermal control and cooling systems for electronic components. This technology has found increasing application in improving the thermal performance of heat exchangers in many industrial environments. The use of heat pipes in heat exchangers allows the development of more compact and efficient equipment, when compared to traditional heat exchangers. For some applications, such as heat recovery in industrial process, the use of heat pipes on heat exchangers presents to be rather interesting due to their direct influence on increasing the efficiency, allowing a more compact design.However, in many thermal control applications, heat pipes using mid-level temperature working fluids, such as water or ammonia, with operating temperatures between 200 K (−73 C) and 550 K (277 C), can hardly operate at steady state conditions. The heat pipe performance depends on its geometry, working fluid, wick structure, and operating conditions. The working fluid is one of the most important parameters as the heat pipe utilizes the phase change to transport the heat. Therefore, the selection of the working fluid is of great importance to enhance the thermal performance of the heat pipe. Heat pipes operating at midlevel temperatures have found several applications in industrial sector. In this work, heat pipes were designed and manufactured with the objective of investigating the potential application of heat pipes operating at mid-level temperature. The thermal conductance obtained from the experimental tests were used to correlate the thermal conductances obtained analytically, with results showing high accuracy based on the adjustment factor applied. The numerical model results were compared with experimental measurements at the same condition. Good agreement was observed between numerical predicted temperature profiles and experimental temperature data. Test results showed reliable operation during the power step and power cycles, with fast start ups, achieving thermal conductances of up 26.59W/ C.