N. Santhi Sree,N. V. V. S.Sudheer,P. Bhramara,




Binary mixtures,closed loop pulsating heat pipe,fill ratio,heat input,thermal resistance,working fluids,


The heat transfer devices involving phenomena of two phase heat transfer are proven to be the best solution for handling moderate to high heat fluxes in different applications. In this regard, an emerging and new technique is “Pulsating heat pipe cooling”, when it comes to the field of electronics thermal management. CLPHP development meets the current requirements for elimination of moving parts in a cooling system. As the demand for effective and small heat transfer devices is increasing, the present paper describes an experimental analysis of a closed loop pulsating heat pipe. Vertical bottom heat mode is considered as the position of CLPHP for the experimental work. PHP consists of a copper tube of length 262 mm, with capillary dimensions of 2 mm and 3.1 mm having internal and external diameter respectively. The tube is bent in a serpentine manner with 8 number of turns and is connected end to end. Before filling the working fluid in the tube, it is first evacuated partially. Based on the total volume, 50%, 60%, and 75 % filling ratios are considered for analysis. Different pure working fluids, viz., Ethanol, Methanol, Acetone and their mixtures, viz., Ethanol-Methanol, Ethanol-Acetone, and Methanol-Acetone are considered for experimentation. The experiments are conducted for different heat inputs varying from 20 to 100 W. The maximum heat input is dependent on the boiling point of the particular fluid. CLPHP is affected by various parameters like heat input, filling ratio, working fluid etc. Acetone shows least thermal resistance value among pure fluids whereas Ethanol-Acetone shows least thermal resistance and better heat transfer performance among mixtures. For low heat input conditions ethanol shows better performance.


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