The effect of nanoparticle shape on the thermal resistance of a flat-plate heat pipe using acetone-based Al2O3 nanofluids

Abstract

In this paper, we experimentally investigate the effect of the shape of nanoparticles in acetone-based Al2O3 nanofluids on the thermal resistance of a flat-plate heat pipe. Acetone-based Al2O3 nanofluids containing sphere-, brick- and cylinder-shaped nanoparticles were prepared, using the two-step method without any surfactants or additives. The flat-plate heat pipes are manufactured with the prepared three nanofluids. The thermal resistances of the flat-plate heat pipes are experimentally obtained. The results show that the thermal resistances of the flat-plate heat pipes with nanofluids containing sphere-, brick- and cylinder-shaped nanoparticles are reduced to 33%, 29%, and 16%, respectively, compared with the thermal resistance of the flat-plate heat pipe with pure acetone. Based on the results, we demonstrate that the shape of nanoparticles in working nanofluids significantly affects the thermal resistance of the heat pipes. Finally, we discuss why nanoparticle shape in nanofluids reduces the thermal resistance of the flat-plate heat pipe using a theoretical approach presented in literature.