C/SiC复合材料表面热化学烧蚀过程模拟OA

C/SiC composites have become key materials for hypersonic vehicle thermal protection systems and aeroengine hot-end components due to their exceptional ablation resistance and high-temperature mechanical properties.Under extreme hypersonic or propulsion environments,complex thermochemical ablation occurs on material surfaces,involving multiphysics coupling of heat transfer,mass diffusion,and multiphase chemical reactions at the surface.Accurate prediction of ablation behavior is crucial for designing thermal protection systems and assessing their reliability.While numerical simulations based on thermochemical equilibrium theory are the primary research approach,their practical application is constrained by deficiencies in algorithms for solving nonlinear equation systems.The widely used Newton iteration method exhibits high sensitivity to initial conditions,frequently resulting in convergence failures or convergence to non-physical solutions.Additionally,the computation of the Jacobian matrix is computationally intensive,leading to inefficiency.These shortcomings limit the robustness and predictive accuracy of existing models,particularly under variable and extreme conditions.Therefore,developing a stable,efficient,and reliable numerical framework for ablation prediction holds significant engineering value.This study introduces a high-fidelity modeling framework to simulate the thermochemical ablation process of C/SiC composites.It employs a surface thermochemical equilibrium model,calculating ablation mass flux by solving a set of nonlinear equations governing mass conservation,energy balance,and multiphase chemical kinetics at the material-gas interface.A novel parametric interpolation optimization algorithm is proposed and applied to pre-compute a multidimensional response surface of ablation rate as a function of key environmental parameters(pressure,temperature,heat flux).During simulation,the ablation rate at a given state is efficiently obtained via interpolation on this response surface,effectively circumventing the iterative convergence issues inherent in Newton's method.This approach ensures computational stability while significantly reducing computational cost.The computed ablation rate is subsequently integrated as boundary conditions into a finite element model developed using COMSOL Multiphysics.This coupled model simulates the transient thermal response and surface retreat process of a C/SiC specimen exposed to a high-enthalpy gas flow.Heat transfer,internal thermal conduction,and the moving boundary caused by surface retreat are fully coupled.The material properties of C/SiC,including thermal conductivity,specific heat,and density,were considered temperature-dependent.The parametric interpolation algorithm demonstrated exceptional robustness and efficiency across a broad parameter range.It successfully generated ablation rate data under conditions spanning pressures from 0.1 MPa to 5 MPa and surface temperatures from 2000 K to 3500 K—conditions where Newton's method often struggled to converge.Finite element simulations provided detailed insights into the ablation process.Results revealed the evolution of the temperature field and the progressive retreat of the surface.The predicted linear ablation after 50 seconds of exposure was 8.246 mm.To validate the model,these predictions were rigorously compared with experimental data from validated plasma wind tunnel tests reported in the literature.The comparison demonstrates excellent agreement.The deviation between simulated and experimentally measured linear ablation remains within±10％.The predicted temperature evolution of the thermal field also closely matched experimental trends.The primary source of residual error stems from the model's current focus on thermochemical ablation,which excludes mechanisms such as mechanical erosion/spalling and internal pyrolysis effects that may cause material loss in certain physical experiments.The proposed parametric interpolation optimization algorithm effectively overcomes the limitations of traditional equation solvers in convergence and stability,enhancing the reliability of ablation prediction.The coupled finite element model successfully reproduces key features of the ablation process,including thermal response and surface retreat,with validation errors within acceptable engineering limits.This provides a theoretical basis for simulating surface ablation materials under extreme environmental conditions.