Numerical simulation of single-phase flow and heat transfer characteristics of three-petal shaped fuel assembly

•A numerical analysis model of a 7-rod bundle three-petal fuel assembly was established.•The flow and heat transfer characteristics of the three-petal fuel assembly under cosine heating conditions were analyzed.•The flow and heat transfer characteristics of three-petal and four-petal fuel assemblies were compared. Petal-shaped fuel rods are an important means to realize reactor miniaturization and high power density. This paper establishes a numerical analysis model of a triangularly arranged 7-rod bundle with three-petal shaped fuel assembly, analyzes the single-phase flow and heat transfer characteristics under cosine heating conditions, and compares it with a four-petal shaped fuel assembly. The results show that the helical structure of the petal-shaped fuel rods can induce lateral fluid flow, generate secondary flow, and enhance the churning ability between fluids. Its unique structure makes the circumferential heat flow density, temperature, and Nussle number (Nu) on the fuel surface periodically non-uniformly distributed. Compared with the four-petal rod, the three-petal rod performs better in the circumferential direction in terms of heat transfer and temperature distribution uniformity. The related research results provide a theoretical basis for the application of petal-shaped fuel elements in reactors.