Heat transfer of an experimentally characterized hybrid nanofluid over a curved surface for nuclear reactor cooling

The current study investigates the nonlinear convection flow of an experimentally characterized ternary nanofluid over a permeable curved heat exchanger tube by incorporating temperature-dependent viscosity and thermal conductivity. The formulated boundary layer equations are presented in a curvilinear coordinate system, accounting for nonlinear thermal radiation, spatially varying volumetric heat generation, convective heating at wall tubes, and viscous dissipation. Experimentally derived equations for viscosity and thermal conductivity for temperatures 25^∘ to 50^∘ and 1.4 to 3% nanoparticle concentrations are incorporated. The nonlinear Boussinesq approximation is employed to capture the large temperature gradient within the boundary layer. The Chebyshev collocation method is employed to solve the compacted equations, and an accord with the literature is established. The study reveals that key parameters such as curvature intensify the fluid’s temperature and entropy generation by about 18% and 22%, respectively, while the skin friction and Nusselt number drop by about 15% and 12%, respectively. The volume heat generation increased the fluid’s temperature by up to 19% but decreased the skin friction Nusselt number and entropy by about 6%, 4%, and 11%, respectively. Thermal radiation elevates the temperature by 14% and the Nusselt number by 8% and drops the skin friction and entropy by about 10% and 7%, respectively. The performance evaluation criterion (PEC) values are obtained as 1.1083, 1.4966, and 1.9179 for the mono, hybrid, and ternary nanofluids, respectively. The ternary fluid exhibits the highest PEC, indicating its superior heat transfer performance over mono- and hybrid mixtures with about 73% and 28%, respectively. These outcomes depict that the ternary nanofluid, with its experimentally validated temperature-dependent properties, provides significant potential for advanced thermal management applications, especially in nuclear energy systems, compact heat exchangers, and high-temperature thermal devices where efficient heat removal and thermodynamic optimization are significant.