An Experimental Investigation on Aqueous Fe–CuO Hybrid Nanofluid Usage in a Plain Heat Pipe

Nanofluids have been widely used as working fluids in thermal systems on account of their enhanced aptitudes on heat transfer. In this paper, an aqueous hybrid nanofluid suspension including Fe and CuO nanoparticles (50:50) was prepared at 2 % mass concentration and utilized as working fluid inside a plain heat pipe under miscellaneous working conditions implemented on both evaporator and condenser regions. As a non-ionic surfactant, Triton X-100 was doped into the hybrid suspension at 0.2 % mass concentration for providing stability and extending the hanging time of the nanoparticles. So as to determine the influence of hybrid nanoparticle inclusion in the base fluid on thermal characteristics, a set of experiments for both distilled water and hybrid nanofluid were executed by considering the same operating conditions. Temperature distributions were measured and recorded. These records were used while calculating the heat pipe’s thermal efficiency and thermal resistance, and improvement rates in both were determined. Experimental findings illustrated that hybrid nanofluid utilization decreased the overall wall temperatures and advanced the thermal efficiency of the plain heat pipe up to 72.63 %. Similarly, the heat pipe’s thermal resistance values were able to be declined up to 0.0070 K·W⁻¹ by hybrid nanofluid usage in lieu of distilled water, which also corresponded to a maximum increment rate of 16.91 %.