Numerical investigation on thermal-hydraulic characteristics of NaK in a helical wire wrapped annulus

Abstract

The wire wrapped on an annulus can act as a structural stabilizer and heat transfer promoter, which is a promising heat transfer augmentation device. The thermal-hydraulic characteristics of NaK in a helical wire wrapped annulus is numerically investigated using structured mesh, with the conjugate heat transfer between the solid and liquid domain being taken into consideration. The sensitivity analysis of the turbulent model and turbulent Prandtl number are conducted. The flow and temperature fields of the coolant are obtained, which show a fully mixing and uniformity. As a cost, the temperature distribution of the solid domain is observed to be non-uniform. The heat transfer is strengthened due to the enhancement of the synergy between the velocity and temperature field. The correlations of the heat transfer coefficient and friction factor are provided. The thermal-hydraulic performance ratio of annulus with and without wrapped wire is 0.92–0.99, suggesting a satisfactory performance. Besides, the average heat flux on the helical wire surface is only 5% of that of loaded on the outer smooth wall of the inner sleeve. This paper may contribute to the thermal-hydraulic design of the liquid metal cooled and helical wire wrapped annulus.