Hydrodynamic-combustion coupling calculation method for water-cooled wall of supercritical boiler by micro-element superposition method

During deep-peak shaving operation, supercritical boilers are frequently subjected to load adjustment states. The water-cooled wall is affected by both combustion conditions and working fluid dynamics during deep-peak shaving processes. Focusing solely on the flue gas side or the working fluid side fails to capture the complete behavior. To improve hydraulic calculation accuracy for the water-cooled wall, this study develops a novel method that accurately couples the hydraulic and combustion processes in supercritical boilers. The coupled model precisely combines boundary conditions, accurately represents hydraulic loops, and enables a comprehensive simulation of the entire water-cooled wall. Compared to existing models, it considers a wider and more detailed range of factors. A 350 MW supercritical coal-fired once-through boiler serves as the research object, with spatial heat flux data obtained from CFD combustion simulations. MATLAB programming is used to assign thermal loads to each tube, while modeling the actual steam-water flow process to form the hydraulic loop. Validation against on-site operational data demonstrates excellent agreement, with a maximum relative error of 8.08 % for outlet wall temperature. Furthermore, the model identifies high-temperature risk areas, aiding safety monitoring under variable load conditions and providing operational guidance for enhanced system reliability.