Numerical Investigation on Laser Ablation Characteristics of C/C Materials Under High-Speed Airflow

Studying the laser ablation characteristics of materials under high-speed airflow and flowfield evolution is of great significance for the thermal protection design of aircraft. A macroscopic numerical method for laser ablation under high-speed flow conditions was developed based on carbon/carbon (C/C) materials. The model includes both oxidation and sublimation processes of C/C materials. For the first time, mass injection effects on ablation characteristics were introduced. Numerical simulations of laser ablation on a flat plate model were conducted under Mach 6 and static conditions. The temperature evolution in the ablation zone was analyzed. Changes in flow characteristics due to ablation injection and high-speed airflow were examined in detail. Additionally, the impact of these flow changes on ablation characteristics was investigated. Results indicate that the airflow significantly affects temperature responses at different wall positions. The isotherms in the ablation zone bend downstream. The total ablation rate at Mach 6 is 5.3% higher than in static conditions. Local flow characteristics are altered by both ablation injection and high-speed flow, creating a high-pressure zone. This zone evolves continuously, leading to pressure variations at different wall locations. These local pressure changes significantly affect the sublimation rate of the wall, thereby influencing the ablation rate.