Thermal performance of mesh wick cylindrical heat pipes using graphite nanofluid

Cooling loads account for a considerable portion of the energy consumption to run many industrial systems. So, devices with passive or lower power ratings that can dissipate bigger thermal loads have a higher industrial value. Heat pipes are passive devices that can transfer large amounts of heat energy based on the principles of boiling and condensation heat transfer. Hence any research focused on to improve heat pipe thermal performance is extremely valuable and has applications in a variety of disciplines, including electronics, nuclear, solar, and space. In the present work, the thermal performance of heat pipes was experimentally analysed by replacing DI water with greater conductivity graphite nanofluids. In terms of performance factors such as thermal resistance, equivalent thermal conductivity, and overall heat transfer coefficient, the effect of nanoparticle concentration and dynamic variables such as tilt angle and heat flux levels on heat pipe operation are investigated. It was found that if the heat pipe is in horizontal mode of operation, the wick capillary alone assists the liquid transport from the condenser. For gravity assisted operations, such that condenser located above the evaporator, the inclination angle has a positive effect on heat pipe performance showing a reduced thermal resistance. However, too much vertical orientation degrades the heat pipe performance due to excess liquid interfering with the nucleate boiling mechanism.it was found that an optimum angle of 60 degree favors the maximum heat transfer. Vaporisation of base fluid and thus heat transfer rate are found to be improved with the use of high thermal diffusivity graphite nanoparticles. A reduction in thermal resistance and an improvement in heat transfer coefficient in comparison with base fluid clearly suggests the suitability of the graphite nanofluid for heat transfer applications.