Numerical investigation on effects of fuel rod with the position of bow deformation on the flow and heat transfer of PWR

The three-dimensional thermal–hydraulic model of 5 × 5 bow fuel assembly is established and its accuracy is verified through a comparison of numerical data with experimental results. Through a comparative analysis of the distributions of thermal–hydraulic parameters, including pressure drop, flow velocity, and axial temperature, the effects of bow deformation at three different places on fluid flow characteristics and heat transmission were determined. Bow deformations at any place result in the dispersion of coolant over many sub-channels, which modifies the thermal–hydraulic parameter distributions substantially. High local temperatures in the coolant are caused by the bow deformation in fuel rods, which alters the local heat transfer dynamics. Additionally, bow deformation has a little effect on pressure variations even if it causes the cross flow to be redistributed, which impacts the coolant's ability to transfer heat. This study provides statistical support and theoretical justification for engineering design applications.