Numerical simulation of mixed convection heat transfer of molten salt in horizontal square tube with single surface heating

A numerical simulation was presented on the mixed convective heat transfer of molten salts in single-side heated horizontal square tube. The flow and heat transfer characteristic of molten salt with bottom, lateral and top heated positions were analyzed, respectively. The results showed that under non-uniform heating conditions, the velocity profiles of main core area changes with the increase of flow distance due to buoyancy effects and the core area is close to heating surfaces. For different heating modes, the numbers of vortex flow formed in each cross section of channel are different. Heat transfer ability is strengthened due to the existence of vortex in different scales. Good agreement between simulation results and mixed convective correlation is reached and the deviation between 92% of simulation results and correlation is within 20%. Under the same heating modes, the heat transfer performance of mixed convection is strengthened 1.2–2.5 times than that of forced convection.