<p>Numerical simulations are conducted in centrally-staged high-temperature-rise swirling combustors to investigate the effects of varying cooling injection inclination angles on liner wall cooling performance. Under constant operating conditions, the analysis examines not only cooling performance but also flow structure, along with fluid-thermal interaction near the liner wall. The results suggest that the behavior of an entire cooling structure is not solely dependent on the characteristics of a single cooling hole. The cooling air proportion is a significant factor affecting the overall cooling performance, while the fluid and thermal interaction near the liner wall is another critical aspect. As the cooling injection inclination angle increases from 30° to 150°, the cooling injection progressively exhibits notable backflow, enhancing the entrainment capability of the corner recirculation zone. Simultaneously, near-wall flow disturbances intensify and evolve into vortices, ultimately forming and thickening the near-wall film while contributing to the development of a low-speed zone. The overall trend of average liner wall temperature rises; the temperature distribution uniformity decreases, and the heat exchange capacity of liner wall diminishes, driven by the formation and intensification of flow disturbances and vortices. At a cooling injection inclination angle of 30°, cooling efficiency remains high with the minimal fluctuations, accompanied by a more uniform and lower average liner wall temperature. The total pressure loss coefficient is 3.9%; combustion efficiency reaches 99.92%, and cooling efficiency is 1.4 times greater than the minimum observed at a 120° angle.</p>