In advanced aero-engines, the pursuit of higher propulsive efficiency and power output creates an imbalance in the supply and demand of cooling air. In response, this study establishes a multi-step optimization platform for the hybrid cooling array, with the dual objectives of improving the cooling efficiency and coolant utilization. The design space involves the impingement hole diameter, film hole pitch in the spanwise and streamwise directions, thickness of the cellular partition and film cooling plate, height of impingement channel, and configuration inclination. Furthermore, two types of coolant supply condition are incorporated into the study. To attain the dual objectives, we specify a fixed constraint on the coolant supply per unit area. Taguchi method is chosen for the initial design of partial factors that have a weak nonlinear relationship with the cooling effectiveness. Optimization is conducted by long short-term memory model combined with manta ray foraging optimization algorithm for the residual factors which maintain a strong nonlinear relationship with the cooling effectiveness. Using the Taguchi method, the optimal combination for maximum cooling performance and relative contribution level of initial design factors have been successfully determined, and a set of mechanism analyses are given accordingly. LSTM model achieved a high reconstruction precision for the laterally averaged cooling effectiveness (ηlat¯) of the hybrid cooling array, with mean absolute error of 0.31 % and 0.83 % for ηlat¯, determination coefficient of 0.9997 and 0.9988 for the area-averaged overall cooling effectiveness (ηov¯), in the training and testing group, respectively. Meanwhile, the optimized cooling array exhibits an encouraging performance, with 8.94 % and 10.37 % improvements on ηov¯ for two coolant supplies, respectively. It is believed that the proposed framework can be generalized to optimize other forms of hybrid cooling array.
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