Numerical investigation of flow and heat transfer characteristics of special-shaped fuel

Abstract

Helical cruciform fuel, a relatively new type of fuel element, has garnered significant interest due to its distinctive attributes, such as transverse mixing characteristics and self-supporting properties. However, helical cruciform fuel still faces numerous challenges. To address the issue of high central temperatures, an annular helical cruciform fuel is introduced, and its internal flow and heat transfer characteristics are evaluated through numerical simulation in comparison to helical cruciform fuel. The results indicate that fuel elements with a helical structure exhibit lower maximum temperatures and higher convective heat transfer coefficients. Specifically, the maximum temperature of helical cruciform fuel at a power density of 200 WM/m3 is 712.26 K, whereas for annular helical cruciform fuel under the same heat generation rate, the maximum temperature is only 686.34 K. Regarding convective heat transfer, the annular helical cruciform fuel element demonstrates an improvement of approximately 20% compared to the helical cruciform fuel element. Consequently, annular helical cruciform fuel contributes more to the safety of the reactor core and the miniaturization of nuclear power devices. This study could serve as a reference for the subsequent design and enhancement of reactor cores.