Natural convection of nanofluids in a cavity: criteria for enhancement of nanofluids

摘要: Purpose The purpose of this study is to theoretically analyze the laminar free convection heat transfer nanofluids in a square cavity. The sidewalls cavity are subject temperature difference, whereas bottom and top insulated. Based on available experimental results literature, two new non-dimensional parameters, namely, thermal conductivity parameter (Nc) dynamic viscosity (Nv) introduced. These parameters indicate augmentation nanofluid by dispersing nanoparticles. Design/methodology/approach The governing equations transformed into form using thermo-physical properties base fluid. obtained solved numerically finite element method. reported for general problem as well case studies isotherms, streamlines graphs average Nusselt number. Using concept Nc Nv, some criteria convective enhancement proposed. As practical cases, effect size nanoparticles, shape type fluids working analyzed. Findings The show that increase magnitude Rayleigh number increases efficiency nanofluids. nanoparticles fluid significantly affects Some cases found, which utilizing deterioration transfer. very crucial issue. decreases transfer, limits capability decreasing systems. Originality/value In present study, separation line based (i.e. Nv) demonstrates boundary between nanoparticles. Indeed, lines, with specified Nv can be simply estimated.