Coupled Aerothermoelastic Modeling And Analysis Of Thermal Protection Panel For Hypersonic Vehicles

The coupled aerothermoelastic analysis is a urgent mission for the thedevelopment of hypersonic vehicle, and directly supports the design of thermalprotection system.Associated with the control and stability, the aerothermoelasticperformance impacts flight attitude and trajectory, and restrict the overallperformance of hypersonic vehicle. Because of the strong interactions amongsub-disciplines, such as aerodynamic pressure, aerodynamic heating and elastic, theaerothermoelastic coupling couldn’t be solved separately, and has become a hotdirection in hypersonic domian. This dissertation, focusing on the thermal protectionpanel of quasi-wavrider hypersonic vehicles, explores coupled aerothermoelasticmodeling and analysis based on the partitioned method. The results attainted are asfollows.(1) Based on the establishing of the aerothermoelastic physical model andsolution model, the coupled mechanics among aerodynamic pressure, aerodynamicheating and structure are analysed, and a temporal evolution algorithm is put forwardfor partitioned simulation.(2) The data interface for multiphysics is explored. The construction principle oftetrahedron in constant volume transfer(CVT) method is explored. Then based on therelationships between point and triangle, an improved data exchange algorithm,namely Inside Projective Constant-Volume Tetrahedron (IPCVT), is proposed, withwhich the algorithm unstability of CVT is well suppressed at great overlaps or gaps ofboundary meshes. It is manifested that IPCVT is applicable for the boundary dataexchange in multiphysics interaction.(3) The engineering calculation method of hypersonic aerodynamic pressure andaerodynamic heating for quasi-wavrider vehicles is put forward. First, the3-Dquasi-wavrider figure is simplified into2-D figure by strip theory, which is followedby calculating the aerodynamic pressure and the shock shape along the strip surfacebased on thin shock layer theory. Then, the entropy and other aerodynamic parameterson the boundary layer edge is achieved according to the mass conservation along theflow pipe. Finally, the aeroheating flow rate is gained by the engineering aerodynamicheating formula. Including the effects of entropy layer, this method has excellentaccuracy, and is appropriate for complex problem such as coupled aerothermoelasticanalysis.(4) The composite cover thermal protection system(CCTPS) for quasi-wavrideris designed. First, a accurate and efficient1-D thermal network is established for rapidthermal analysis. Secondly, the structure of thermal protection layer and thickness ofthermal insulation layer are designed. Then, the thermal and mechanical performancesof the CCTPS is checked. Finally, the characters of the thermal protection panel are analysed for the physical and numerical models of coupled aerothermoelasticanalysis.(5) The techniques of coupled aerothermoelastic analysis are explored in detail.Firstly, based on the piston theory, a solution method for coupled aerodynamicpressure-displacement is proposed with definite rank of approximate expression, andthe influence of panel normal disturbance velocity on coupled response isinvestigated. Secondly, the strategy of coupled transient aeroheating-temperature fieldis analysed, and a method for coupled parameters is put forward for the efficiency ofcoupled analysis. Finally, according to the interaction principle between temperaturefield and structure displacement field, a sequent coupled solution method is proposed.(6) Further analysis and applications of the coupled aerothermoelastic responseare accomplished for the thermal protection panel. First and foremost, based on theinfluence of aeroheating time step on the coupled response, the adaptive aeroheatingtime step method is presented, with which the occasion of aerodheating calculation isso reasonable that the efficiency and accuracy are improved greatly. Besides, how thecoupled degree and rigid body aerodynamic pressure time step affect the coupledresponse of quasi-static aerothermoelastic is discussed. Last but not the least, the“biaxial” connector is designed for releasing the local severe shear stress near theattachment with little panel edge deformation, and can be used to install the CCTPS.The research of this dissertation is a innovative application of coupledaerothermoelastic technique on quasi-wavrider hypersonic vehicles, which couldprovide some relative analysis and demonstrating methods for other hypersonicvehicles with severe aerothermoelastic problem. Moreover, some methods andconclusions can be generalized to other fields, with good engineering practicabilityand populazation.