Predictive analysis of the overall cooling effectiveness for leading-edge showerhead cooling based on a thermal resistance network model with physical corrections

For turbine blade leading edge showerhead cooling structures characterized by conjugated heat transfer, an overall cooling effectiveness prediction model is developed based on a thermal resistance network. Multiple prediction routes are established, enabling a systematic assessment of the relative influence of different correction strategies. Model inputs and reference data are obtained from numerical simulations under realistic engine operating conditions, and experimental measurements of guide vane overall cooling effectiveness are employed to validate the numerical approach at the integral thermal-response level. The results indicate that the external heat transfer coefficient at the leading edge exhibits a stable and predictable streamwise distribution, making it suitable as a reliable model input, whereas the film cooling effectiveness is highly sensitive to the hole arrangement and coolant mass flow ratio, governing local prediction accuracy through its spatial coverage and streamwise decay. The heat transfer area and curvature corrections have a limited influence on the overall prediction level, whereas the conjugated heat transfer correction within the film-cooling holes significantly enhances the local responses near the hole rows, accompanied by localized peaks. Lateral conduction correction effectively suppresses local overprediction and markedly improves spatial continuity and stability. The final corrected model predicts the leading edge overall cooling effectiveness within ±10 % for all coolant mass flow ratios considered, with errors reduced to within ±5 % at higher mass flow ratios. Based on the corrected model, a leading edge η–h_c mapping relationship is established, providing quantitative guidance for parameter selection and design margin evaluation of composite cooling structures.