Role of graphene nanofluids on heat transfer enhancement in thermosyphon

The thermophysical properties of graphene nanofluids in thermosyphon have been studied at different power inputs, temperatures and angles of inclination. The thermal conductivity of the graphene nanofluid is found to be 29% higher than that of the deionized water at 45 0C.
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Role of graphene nanofluids on heat transfer enhancement in thermosyphon Journal of Science: Advanced Materials and Devices 4 (2019) 163e169 Contents lists available at ScienceDirect Journal of Science: Advanced Materials and Devices journal homepage: www.elsevier.com/locate/jsamdOriginal ArticleRole of graphene nanofluids on heat transfer enhancement inthermosyphonSidhartha Das a, *, Asis Giri a, Sutanu Samanta a, S. Kanagaraj ba Department of Mechanical Engineering, North Eastern Regional Institute of Science and Technology, Nirjuli, Arunachal Pradesh, 791109, Indiab Department of Mechanical Engineering, Indian Institute of Technology, Guwahati, Assam, 781039, Indiaa r t i c l e i n f o a b s t r a c tArticle history: The thermophysical properties of graphene nanofluids in thermosyphon have been studied at differentReceived 28 October 2018 power inputs, temperatures and angles of inclination. The thermal conductivity of the graphene nano-Received in revised form fluid is found to be 29% higher than that of the deionized water at 45 C. The viscosity of the graphene21 January 2019 nanofluid increased with the concentration of graphene nanoparticles and decreased with increasing theAccepted 22 January 2019Available online 30 January 2019 temperature. It is observed that the wall temperature distribution of graphene nanofluid is found to be decreased in comparison to that of deionised water. The thermal resistance of thermosyphon is reduced with increasing the power input and irrespective of the inclination angle.Keywords:Graphene platelet nanoparticle © 2019 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.Thermosyphon This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Thermal conductivityViscosityThermal resistance1. Introduction 0.075% involving a thermal load ranging from 40 W to 210 W. They observed a decrease in the thermal resistance of the heat pipe up to Tremendous demands for higher heat transfer devices exist due 65% for 0.05 vol.% of Al2O3 and 57% for 0.075 vol.% TiSiO4. Kole andto the advancement of microelectronics, which necessitate better Dey [3] examined surfactant free water based copper nanofluidsthermal management solutions. A thermosyphon is a device, which and observed a thermal conductivity enhancement of 15% foruses the phase transformation of a working fluid to transport heat 0.5 wt.% at 30 C. Further, the nanofluid was used in the wicked heatand therefore heat transport by this device is fundamentally higher pipe, which indicated a thermal resistance as low as 27% at higherthan any highly conducting material having same cross section. thermal load. Al2O3, CuO and laponite in water caused the decreaseThus, the boiling characteristics, vapour pressure, thermal con- of the performance of heat pipe. This was reported by Khandekarductivity and surface tension of the working fluid play an important et al. [4]. It was predicted that nanoparticles entrapment in therole in the performance of thermosyphon. Nanofluid, solideliquid grooves of the rough surface was the reason for such behaviour. Thesuspension is produced by dispersing nanoparticles with the oscillating heat pipe (OHP) was examined by Qu and Wu [5], byworking fluid. A lot of research has been carried out to enhance the using Al2O3/water and SiO2/water nanofluids, where a reduction inthermal performance of the thermosyphon using nanofluids. thermal resistance was found for both the working fluids. Noie et al. [1] conducted an experimental study on the two- Using water-based TiO2 and Au nanofluids, Buschmann andphase closed thermosyphon (TPCT) using Al2O3/water nanofluids. Franzke [6] investigated thermal performance of heat pipe. AThe efficiency of TPCT was found to enhance up to 14.7% for a maximum reduction in the thermal resistance of 24% was observedconcentration ranging from 1 to 3 vol.%. TPCT filled with water- from the experiment. The performance of refrigerant based Tibased Al2O3 and TiSiO2 nanofluids was investigated by Kamyar nanofluid was observed in a heat pipe by Naphon et al. [7]. Anet al. [2] for a nanoparticle loading of 0.01%, 0.02%, 0.05% and optimum condition was revealed for a heat pipe with 0.1% nano- particle concentration, which provided 1.4 times higher efficiency * Corresponding author. than the pure refrigerant. The expe ...