EXPERIMENTAL STUDY ON IMPROVING HEAT TRANSFER ABILITY OF A HEAT PIPE UTILIZING IRON OXIDE-FERRIC OXIDE HYBRID AND NICKEL FERRITE MONO-MAGNETIC NANOFLUIDS

Heat carrier refining of a heat pipe employing the iron oxide-ferric oxide hybrid magnetic nanofluid and nickel ferrite mono-magnetic nanofluid as an operating medium in the process of various performing conditions was investigated experimentally. A thermosyphon-type heat pipe constructed of copper with 20-mm internal and 18-mm external diameters was used in this experimental work. The fulfillment of the heat pipe was examined by operating three separate operating fluids: distilled water, hybrid and mono-magnetic nanofluids. The fluid was injected into the system with a filling ratio equal to 1/3 of the total volume of the heat pipe for all individual experiments. Practical analysis was performed under three distinct input heats and two different nanofluid weight percent as an operating medium in the evaporator section and three different coolant mass flow rates in the condenser area of the system. Wall temperature fluctuations, index factor (efficiency), Nusselt number, and thermal resistance magnitudes were obtained for distilled water, iron oxide-ferric oxide hybrid magnetic nanofluid, and nickel ferrite mono-magnetic nanofluid for each experiment. The highest improvement rates in heat transfer ability, Nusselt number, and heat pipe thermal resistance magnitude were 30.55%, 26.9%, and 61.8%, respectively, when the iron oxide-ferric oxide hybrid magnetic nanofluid was employed as an operating fluid compared to distilled water. The thermal performance of the system increased significantly with increasing the weight percent of both hybrid and mono-magnetic nanofluids. Basically, the efficiency of the system was improved by 3.92% by increasing the weight percent of the hybrid magnetic nanofluid from 0.5 wt.% to 1 wt.%.