熔盐沿螺旋十字型单棒层流混合对流传热数值研究

The concept for FuSTAR, a small fluoride salt-cooled high-temperature reactor, was proposed by Xi'an Jiaotong University, and the helical cruciform fuel assembly is adopted for FuSTAR. In order to study the mixed convection heat transfer characteristics of molten salt in the helical cruciform fuel assembly, a helical cruciform single-rod channel model is established. The computational fluid dynamics (CFD) method is used to verify the numerical calculation model with experimental data. The difference between the numerical calculation value and the experimental measurement value of 94% wall temperature data point is within ±5℃, and the relative error between the numerical calculation value and the experimental measurement value of 94% average heat transfer coefficient data point is −15%~15%. The results of mixed convection heat transfer of molten salt along helical cruciform single-rod show that the influence of natural convection on the whole mixed convection heat transfer is related to inlet temperature and heat flux. The effect of natural convection on overall convective heat transfer can be more accurately evaluated by Φ/Gz (Φ is the combination variable of dimensionless number of natural convection, and Gz is Graetz number). In addition, the correlations of laminar mixed convection heat transfer of molten salt along helical cruciform single-rod at 30≤Re≤500, 6≤Pr≤26, 600≤Gr≤42000 are fitted(Re is Reynolds number, Pr is Prandtl number, and Gr is Grashof number).