Investigation of the effects of base fluid type of the nanofluid on heat pipe performance

摘要

Most recently, an ascending tendency in nanoparticles containing working fluid utilization has been observed in such thermal systems as double pipe heat exchangers and thermosiphons in so far as its advantages upon the performance of such systems. In order to investigate how the type of the base fluid affects the nanofluid’s properties used for thermal applications, an experimental test rig was setup and two different nanofluid each of which involves different base fluid, but same nanoparticles and surface active agent were tested. During the nanofluid preparation process, bauxite nanoparticles as nanoparticle material and sodium dodecyl benzene sulfonate as surface active agents were used in volume fractions of 2% and 0.5%, respectively. As the base fluid type, ethylene glycol and deionized water were utilized. The tests were conducted under diverse working conditions and vacuum pressure. Distribution of temperature ahead the heat pipe wall, efficiency and heat pipe’s thermal resistance was experimentally investigated. It was observed from the experiments that each nanofluid improved the heat pipe performance significantly; however, deionized water/bauxite nanofluid gave the best results in terms of heat pipe’s thermal performance. For each nanofluid, the maximum increment in efficiency was observed under 200 W heating power and 10 g/s cooling water mass flow rate conditions, and improvement rates were 29.5% and 13.3% for ethylene glycol-based and deionized water-based nanofluids, respectively. At least 20% of decline in thermal resistance of the heat pipe was also recorded, when nanofluid was employed as working fluid.