Research On Ablation Behavior Of Carbon/phenolic Composites

Carbon/phenolic composites, as a new type of lightweight thermal protection material, is mainly used for blunt body’s heat protection, for the thermal protection materials is a large proportion of the aircraft and its redundancy design has a key role to the quality control of the whole aircraft, so the accurate grasp of its ablation characteristics can solve excessive redundance or the problem of insufficient reliability about thermal protection design. In this paper, in a typical service environment, the carbon/phenolic composites’ volume ablation mechanism and multi-physics-coupling process are studied, and with FEM method, equation about multi-physics coupling is solved. Meanwhile, in a low heat flux environment, thermal and mechanical response of carbon/phenolic composites is analyzed, which supports the thermal protection requirements for hypersonic aircraft. In this paper, the main content includes:Carbon/phenolic composites’ multi-physics-coupling mechanism is studied under the condition of volume ablation. Under convection and thermal load, during the carbon/phenolic composites’ volume ablation process, the coupling relationship among heat transmission, pyrolysis gases flow, Thermal chemical reaction and the thermal stress is given, and the mechanism of heat is analyzed. Energy equation, gas phase diffusion equation, thermal chemical reaction rate equation and equilibrium differential equation are estabulished.Numerical solution is given for multy-physics-coupling ablation. Based on FEM software COMSOL and the ablation model, the ablation process of carbon/phenolic composites is simulated. In a low heat flux and medium enthalpy convection heat load,the temperature field, displacement field, pyrolysis gas pore pressure field, and mechanical response accordingly are forecast.According to the research before, For different material performance parameters and pneumatic thermal environment parameters, carbon/phenolic material is studied, the influence of different factors is given. Finally, significant factors of carbon/phenolic composites’ ablation are specified.