Supercritical carbon dioxide(S-CO_2) power generation technology offers better flexibility

and its substitution for steam power generation technology in the field of thermal power generation is of significant strategic importance for constructing a new type of power system

establishing a modern energy system

and achieving the “dual carbon” goal. Through numerical simulation and experiment

the flow and heat transfer characteristics of S-CO_2 boilers within the actual operating range are analyzed

and the influence of working fluid flow states and physical properties on heat transfer and resistance performance is also investigated. The results show that

the heat transfer coefficient of CO_2 decreases with the thermal conductivity under the same flow conditions. This is because the thermal resistance of the fluid boundary layer increases as the thermal conductivity decreases. Under the same thermal conductivity conditions

the heat transfer coefficient of CO_2 increases with the Reynolds number(Re). The reason is that the fluid boundary layer becomes thinner as Re increases

reducing the boundary layer thermal resistance. For CO_2 working fluid inside the pipe with pressures ranging from 3 MPa to 30 MPa

enthalpy values of 500～1 150 kJ/kg

and Re between 1.1×10~5 and 2.1×10~6

a correlation formula for heat transfer considering boundary layer property corrections is derived. The average deviations are 3.33%

demonstrating it has high precision. The research lays a solid foundation for the design and research of subsequent S-CO_2 boilers.