Experimental Study on Thermal Performance of Dual Diameter Closed Loop Pulsating Heat Pipe Using ZnO/water Nanofluid

Abstract

Abstract: In this paper, experimental study on the thermal performance of closed loop pulsating heat pipe (CLPHP) with single diameter and dual-diameter structure is investigated. The CLPHP with dual-diameter configuration is made of copper capillary tubes with two diameters; greater in the condenser section (inner diameter of 3mm) and smaller in the evaporator and adiabatic sections (inner diameter of 2mm). Experiment was conducted in vertical orientation with bottom heating mode having two-turns and 50% filling ratio (FR). The water and zinc oxide (ZnO/water) nanofluid with 0.25% and 0.5% w/v used as working fluids. The heat power was supplied from 8 W to 80 W, in the steps of 8 W. The various temperatures were recorded on the outer wall of the evaporator and condenser section of single diameter and dual diameter CLPHP. The thermal performance is measured in terms of thermal resistance. The thermal resistance at different heat inputs was measured. It is concluded that, the thermal performance of the dual-diameter configuration is better than the single-diameter.