The supercritical CO₂ coal-fired power generation system is a key future low-carbon technology, prized for its flexibility and efficiency. However, uneven flow and heat distribution in boiler cooling walls can cause temperature imbalances, deformation, and even tube bursts. This paper develops a 2D distribution manifold and 3D cooling wall tube model to study flow and heat transfer under non-uniform flow distribution, validating the model with experimental data. The study examines how tube spacing and diameter affect heat transfer and flow deviation in cooling walls under non-uniform heat flux. A new cooling wall design incorporates tapered inlets and optimized diameters to regulate flow distribution, reduce heat-absorption deviation, and better match flow rate with non-uniform heat flux. Results show that with a tube spacing of 0.4m and inner diameter of 13.35mm, the cooling wall's surface temperature drops by 19.91-63.72K, while outlet temperature non-uniformity decreases by 19.6%. With tapered tube sections (8°-12° cone angle), the maximum wall temperature decreases by 8.4-14.64K and outlet temperature non-uniformity drops by 9.7%. The tapered tube cooling wall design effectively lowers both wall temperature and outlet temperature variation, offering a new approach for cooling wall optimization.
 

supercritical carbon dioxide, cooling wall, non-uniform flow distribution, manifold