Effect of pure and binary fluids on closed loop pulsating heat pipe thermal performance

This paper presents preliminary experimental results on thermal performance of closed loop pulsating heat pipe (PHP) using copper tube having internal and external diameter with 2.0 mm and 3.6 mm respectively. For all experimentation, filling ratio (FR) was 50 %, ten turns and different heat inputs of 10 to 100W was supplied to PHP. The position of the PHP was vertical bottom heat mode. The equal length of evaporator, adiabatic and condenser section was maintained 50 mm. Working fluids are selected as Methanol, ethanol, acetone, water and different binary mixtures. In order to study, characteristics of the thermal resistance and average evaporator temperatures at different heat input for various working fluids. Experimental study on PHP indicated working fluid is an important factor for the performance of PHPs. The result shows that, the thermal resistance decreases more rapidly with the increase of the heating power from 20 to 60 W, whereas slowly decreases above 60 W. Pure acetone gives best thermal performance in comparisons with the other working fluid. No measurable difference has been recorded between the PHP running with pure and binary mixture working fluids. (C) 2013 The Authors. Published by Elsevier Ltd.