Abstract: The temperature field distribution of frame mold during composite autoclave process directly determines the forming quality of composite components. In this work, thermal-fluid coupling topology optimization is implemented using the variable density method. A dedicated topology optimization design framework for frame mold is established, alongside a corresponding design strategy for internal airflow channel. For large-scale frame mold with complex curved surfaces, the continuous adjoint method is adopted for sensitivity analysis. On the premise of retaining the template and main support frames to ensure structural stiffness, the optimal design of the internal airflow channels within the mold is carried out.. Based on the topology optimization outputs, a flow straightener structure is proposed, which substantially improves temperature uniformity across the mold forming surface. The simulation results show that the flow straightener structure significantly improves the air velocity in the low-temperature area at the middle and rear parts of the mold. Among them, the air velocity near the lowest temperature area increases from 1.53 m/s to 2.48 m/s, which effectively enhances the convective heat transfer effect of the template. The maximum temperature difference on the mold profile decreases from 30.7 K to 25.7 K, with a reduction rate of 16.3%. The outcomes of this study offer a robust technical reference for designing internal flow-guiding structures of frame mold, and can effectively enhance the temperature uniformity of mold forming surfaces.

Key words: autoclave process, frame mold, temperature field optimization, thermal-fluid coupled, flow channel