| The non-metallic seal of engine nozzle is in high temperature,high pressure and deflection polarization and other high parameter working environment.If the seal structure is improperly designed,it is easy to yield,extrusion,wear and leakage,resulting in seal failure,thus affecting the operation performance and safety of the whole engine.In order to improve the nonmetallic sealing performance of nozzle,a new type of C-O-ring + X-ring combined seal is designed in this paper,and its sealing performance and structure optimization are systematically studied by numerical analysis and test verification.According to the actual conditions of engine nozzle such as high temperature,high pressure and deflection polarization,the performance analysis model of nonmetallic composite seal of engine nozzle was established by using ABAQUS software based on the numerical analysis method of thermal-solid coupling.The distribution law of equivalent stress,contact stress and friction force of the combined seal was calculated,and the sealing mechanism of the combined seal was explored.It is found that C-O ring is the main sealing channel,and only when C-O seal fails,X-ring can play the sealing role.The accuracy of the model is verified by comparing the friction force calculated by the model with the experimental results.Von Mises stress,effective contact width,effective average contact pressure,maximum shear stress,maximum extrusion width and friction force were defined as the evaluation indexes of seal performance.The influence of structural parameters such as different rubber hardness,high temperature and high pressure,deflection and polarization conditions,sealing compression rate,groove width,groove chamfer and sealing ring size on the sealing performance of nozzle was analyzed.It was found that the working pressure and structural parameters had the greatest influence on the sealing performance,and the optimal range of structural parameters of non-metallic composite seal of nozzle was obtained.Based on the results of numerical analysis,six performance evaluation parameters were taken as optimization objectives,and the response surface method and BBD method were used to design experiments,and the optimization model was established.The multi-objective optimization analysis of C-O composite seal was carried out by using the satisfaction function method to obtain the best structural parameters.Compared with the model before and after optimization,it is found that the nonmetallic composite sealing performance of nozzle has been greatly improved.The parametric simulation software of nozzle seal was developed to solve the problems of complex simulation modeling and time-consuming analysis.The software has the functions of parameter input,simulation setting and sealing performance simulation result output.The design of nozzle seal parametric software calculation results are accurate,the maximum error between software calculation and test is less than 7%.The non-metallic composite seal performance test bench of nozzle was independently designed and built to analyze the leakage and friction of the composite seal under variable parameters.The tensile and compression testing machine was used to explore the resilience of the C-O-ring combination.The test results verified the accuracy of the numerical simulation analysis.In this paper,through numerical simulation analysis and experimental study of non-metallic composite seal of engine nozzle,the structure of non-metallic composite seal of nozzle was optimized,effectively improving the sealing performance of nozzle,providing a new research idea for the sealing performance and structure optimization of non-metallic seal under high parameters,which is helpful to promote the engineering application of this kind of seal. |
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