Research On Thermal Cycle Analysis And Modeling Technology Of Scramjet

In the initial design process of hypersonic vehicle control system,in order to shorten the design cycle and reduce the research cost,it is necessary to establish a control-oriented scramjet engine model with high precision and good real-time performance.Due to the hypersonic working environment,the internal flow field of scramjet engine is complex.In order to meet the accuracy requirements of the model,the internal flow field needs to be fully considered in the modeling process,while the real-time requirement needs to reduce the calculation complexity of the model to improve the calculation speed.Considering the contradiction between accuracy and real-time performance of scramjet engine model,this paper analyzes the main influencing factors of the internal flow field on the thrust performance of scramjet engine from the perspective of thermodynamic cycle.Based on scramjet engine digital simulation model with the component-level characteristics,the research on modeling technology of scramjet engine is carried out considered the main influencing factors of the internal flow field,the specific contents of the study are as follows:Firstly,the thrust is the characterization parameter of the scramjet engine.According to the actual thermodynamic cycle analysis of the scramjet engine,the thrust performance was in one-to-one correspondence with the total pressure recovery coefficient at the same heating ratio,The aerodynamic problems such as the shock reflection and the interaction between the shock wave and boundary layer during the compression process,and the heating law during heating process were the main factors influencing the thrust performance.Based on the T-S diagram,the characteristics of different heating laws and the characteristics of combined heating law were studied.The multi-stage combustor profiles was given under the combined heating law.Secondly,aiming at the aerodynamics problem in the process of compression,an equivalent calculation method based on the principle of hypersonic aerodynamics was given.A modeling method of scramjet engine was proposed considered the main influencing factors of the internal flow field,and at the same time modeling methods of the inlet,the isolation and the multi-stage combustion were proposed based on the above equivalent calculation methods.The influence of the combustion back pressure was considered in the isolation modeling process on its working state.Finally,the simulation of the inlet and the isolation model was carried out.The results show that it can simulate the characteristics of its main flow field.An optimization design method of scramjet engine profile was proposed based on the mixed penalty function method,which was better than the optimization results based on genetic algorithm.At the same time,the real-time performance of the scramjet engine model was verified,and the average engine model calculation time of single state point was 0.25 s.The thrust performance is analyzed based on the throttling rate distribution using SQP algorithm.The conditions of the optimal throttling ratio distribution on the Dynamic pressure were analyzed.