Simulation of Thermal Distribution of Large Hollow Beams Frame Mold and Model Optimization

Compared to traditional ribbed frame-type molds, the hollow beam frame-type mold features the advantages of low heat absorption, rapid heat transfer, and excellent ventilation, making it more suitable for autoclave curing and forming of large aircraft composite panels. This study analyzed the thermal distribution of large hollow beam frame-type molds based on fluid-solid coupling model, and proposed the method of equivalent thermal physical parameters. This method effectively addresses the computational difficulties caused by mold massive meshing, and the reliability of temperature calculation obtained by equivalent model was verified. The results indicate that reducing specific heat capacity can significantly minimize the temperature lag on the mold surface, and increasing thermal conductivity can alleviate temperature differences of the mold surface. After optimizing equivalent thermal physical parameters, the equivalent model prediction error is only 0.24 ℃ when specific heat capacity is 128.75 J∙(kg∙K)⁻¹ and thermal conductivity is 26.64 W∙(m∙K)⁻¹. Furthermore, the equivalent coefficient is independent of heating/cooling rates or model dimensions. Through progressive model scaling, the study achieves thermal distribution prediction for an 8 m complex hollow beam frame-type mold. The computational efficiency increases by over 17 times and the prediction error is below 5%.