Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
EXPERIMENTAL EVALUATION OF THERMAL PERFORMANCE AND INTERNAL PRESSURE OF THERMOSYPHONS USING GRAPHENE OXIDE NANOFLUID
Submission Author:
Thiago Antonini Alves , PR , Brazil
Co-Authors:
Victor Vaurek Dimbarre, Guilherme Antonio Bartmeyer, Pedro Leineker Ochoski Machado, Rozane de Fatima Turchiello, PAULO HENRIQUE DIAS DOS SANTOS, Thiago Antonini Alves
Presenter: Victor Vaurek Dimbarre
doi://10.26678/ABCM.COBEM2021.COB2021-1961
Abstract
Thermosyphons are highly efficient passive heat transfer devices capable of transferring thermal energy in small temperature gradients through the latent heat of vaporization, operating in a two-phase cycle. Such devices are composed of an evacuated metallic tube filled with a working fluid. The objective of the present work was to experimentally investigate the influence of working fluid on the thermal performance of thermosyphons and to verify its internal pressure variation. In this study, the working fluids used were distilled water and graphene oxide nanofluid. The devices were manufactured in copper, with an outer diameter of 9.52mm, an inner diameter of 7.94mm, and a length of 515mm. The evaporator had a length of 265mm, while the adiabatic section and condenser had lengths of 70mm and 180mm, respectively. The thermosyphons were filled with 50% of the evaporator volume. The devices were experimentally tested at a slope of 90° from the horizontal under thermal loads ranging from 5 to 25W at the evaporator and cooling of the condenser by air forced convection. The devices also had a pressure transducer attached, which allowed the evaluation of the pressure variation for the different working fluids, and thermal loads. The thermal analysis was based on the temperature distribution along the length, operating temperature, and thermal resistance. The thermosyphon filled with graphene oxide nanofluid presented lower temperature and thermal resistance values, showing itself as the device with the best thermal performance for the experimental conditions it was submitted. The methodology for measuring the internal pressure showed itself satisfactory when comparing the internal pressure of the water-filled device with the analytical vapor pressure, but, regarding both fluids, it was inconclusive which one presented lower internal pressure values due to the experimental uncertainties.
Keywords
Thermosyphon, Internal Pressure, Thermal performance, Nanofluid, graphene oxide
