Experimental Study On Ablation Performance Of Laminated Anti/Thermal Insulation Composites

In recent years,with the rapid development of China's aerospace industry,new requirements have been put forward for the selection of materials and structural design of solid rocket motor nozzle diffusion section.During the operation of solid rocket motor,the thrust of the engine changes with time,so the heat flux acting on the diffusion section of the motor nozzle changes with time.Through the motor run test time and cost of capital is too high,and difficult to realize real-time detection,so the forecast by the simulation calculation laminated/proof heat insulation material response under the change of heat flow density function,through the model to predict the temperature response of the ablation behavior of materials,provide a reference basis for solid rocket motor nozzle design.In this paper,the laminated composite material is composed of two layers with different functions and effects,the outer layer is carbon/phenolic composite material and the inner layer is high silica materials.A new laminated composite material is prepared,which can be used in the diffusion section of the solid rocket motor nozzle.In order to predict the ablation behavior of laminated materials,the following related studies were carried out.In this paper,the TG curves obtained from TG tests were analyzed by Gaussian peak separation method,and the pyrolysis kinetic parameters were obtained.The relationship between the material conversion rate and temperature was calculated based on the calculated pyrolysis kinetic parameters,and the calculated results were compared with the results of thermogravimetric test to prove the accuracy of the pyrolysis kinetic parameters,and then the change rule of the laminated material conversion rate with temperature in the ablation process was obtained.Multiple oxygen-acetylene ablation tests were carried out to obtain the temperature response curves at different positions on the surface and inside of the material.The mass ablation rate and linear ablation rate of the laminated material were calculated by the mass and size changes of the specimens before and after ablation.The change law of material porosity along the thickness direction was obtained by observing the surface of the specimen before and after ablation test.Through theoretical derivation of the mathematical model,the process of ablation using multiple physical field coupling software COMSOL laminated material ablation model,realize the transient solution of physical field coupling,the simulation results with the model of the laminated prevention/thermal insulation composite material ablation test of temperature response consistent change rule and error in the acceptable range,The changes of pyrolysis degree,pyrolysis rate,porosity and density distribution of the laminated materials during the ablation process were obtained through calculation,and the ablation behavior of the laminated materials under complex environment was reasonably predicted.