Study on the thermal-mechanical performance of supercritical carbon dioxide cooling in horizontal tube under ocean rolling condition

Accurate prediction of heat transfer performance of the S-CO2 under ocean rolling condition is crucial for the fourth-generation Brayton cycle system design of floating nuclear power plant. Compared to land-based stationary state, ocean rolling motion acting on the non-homogeneous distribution of the S-CO2 can generate an inertial force field that includes centrifugal force, tangential force, and Coriolis force, significantly affecting heat transfer performance. This study focuses on the impact of ocean rolling motion on the flow and heat transfer characteristics of the S-CO2 cooling inside a horizontal tube. The analysis results indicate that different mass flow rates and heat fluxes can induce varying buoyancy effects and secondary circulation flow, which leads to differences in the turbulence diffusion near the tube wall. The degree of periodic enhancement and weakening of the local heat transfer coefficient induced by the ocean rolling motion will also vary accordingly. Different ocean rolling motion parameters can alter the magnitude of the inertial force field, thereby affecting the amplitude and intensity of the fluid oscillation. This leads to periodic fluctuation in the local heat transfer coefficient and wall temperature. The maximum wall temperature fluctuation can reach up to 24.21 K, which can induce thermal stress and fatigue.