Experimental study on heat transfer enhancement of carboxylate multi-wall carbon nanotubes in a 3D pulsating heat pipe with a corrugated evaporator

Abstract

ABSTRACT In this research, the thermal performance of a three-dimensional pulsating heat pipe with 11 turns is investigated experimentally. Carboxyl-functionalized multi-walled carbon nanotubes with 0.1 wt% in a water-based fluid are used as the operating fluid. Experiments are performed at 50% and 60% filling ratios, and the effect of grooving the evaporator tubes has also been investigated. Experiments with distilled water were also performed to compare the effect of the nanofluid. Experimental results show that the heat transfer performance of the device depends mainly on the power input and the filling ratio, working fluid, and also, the corrugated evaporator that significantly improves the thermal performance. The use of nanofluids reduces the thermal resistance by about 13% compared to pure water at a filling ratio of 50%, and an input power of 300 watts. At a filling ratio of 60%, and the use of nanofluid, corrugating the evaporator reduces the thermal resistance by 6% in comparison with non-corrugated tubes. In general, and in all cases, with increasing input power, the thermal resistance also decreases.