Numerical Study on the Optimization of Petal-Shaped Fuel Rod Arrangement and Heat Transfer Enhancement Mechanism

Abstract

In this paper, four new arrangements are designed to enhance heat transfer by changing the spiral direction of the ribs around petal-shaped fuel rods. Based on the comprehensive performance evaluation index, it is determined that Pattern-2 arrangement has the best performance among the four arrangements. Further comparison of the heat transfer performance in each sub-channel between Pattern-2 arrangement and original arrangement reveals that the heat transfer coefficients in four types of sub-channels, namely S1-1, S1-6, S2-1, and S2-3, are significantly improved in Pattern-2 arrangement. This is because Pattern-2 arrangement can significantly enhance the coolant flow on the leeward side of fuel rods, thereby reducing the thickness of velocity boundary layer and thermal boundary layer, strengthening the mixing of hot and cold fluids, and thus greatly improving the convective heat transfer performance in the leeward area.

Keywords: Small-scale nuclear reactor, Petal-shaped fuel rod, Fuel rod arrangement, Heat transfer, Numerical simulation