The supercritical carbon dioxide Brayton cycle power generation method has attracted wide attention due to its advantages of high efficiency and compactness. In order to more accurately characterize the aerodynamic properties of the supercritical CO2 (S-CO2) coal-fired boiler under variable operating conditions

this paper presents the aerodynamic properties of a 300 MW divergent recompression primary reheat S-CO2 boiler under variable operating conditions by combining numerical simulation and the moving grid method. The results show that

under the same operating condition

the mass flow rates of superheated and reheated air-cooled wall are lower in the middle and higher at both ends; the pressure drop

outlet air temperature

and tube wall temperature are higher in the middle and lower at both ends

which are just the opposite to the trend of the flow rates; the flow rate deviation shows a W-shaped distribution. In the process of variable operating conditions

as the load decreases

the mass flow rates

pressure drop

and tube wall temperature of the superheated air-cooled wall and reheated air-cooled wall decrease with the load in the four walls

and the outlet air temperature does not show obvious correlation with load

and the outlet air temperature is obviously higher than that of the Rankine cycle unit under the same load. Research indicates that the aerodynamic characteristics of the variable-load air-cooled walls in S-CO2 boilers exhibit distinct distribution patterns and load dependence

providing a basis for unit optimization.