NUMERICAL INVESTIGATION OF MOLTEN SALT-BASED NANOFLUID LAMINAR HEAT TRANSFER IN A CIRCULAR TUBE USING EULERIAN-LAGRANGIAN METHOD

Molten salt-based nanofluid in a laminar region of a circular tube with constant wall heat flux was numerically investigated. An Eulerian-Lagrangian method, discrete phase model, was used to predict the heat transfer performance of nanofluid, considering the factors of inlet Reynolds number, the mass concentration of the nanoparticles, and nanoparticles diameter. Validation results were found in a good match with experimental results obtained from the literature. Numerical results showed that the heat transfer performance of nanofluid was considerably better than that of pure molten salt. The local heat transfer coefficient and Nusselt number of nanofluid are about 30% higher than these of pure molten salt and increase with an increase of Reynolds number and nanoparticles concentration. Moreover, the heat transfer performance of nanofluid with the small size of the nanoparticles (10 similar to 100 nm) is improved significantly.