The Calculation And Analysis Of Aerodynamic Heating Distributions For The Hypersonic Aircrafts

Strict performances of aerodynamics and requirements of thermal protection are put forward for the hypersonic aircrafts. The achievements of aerothemodynamic research have certain value of theory and engineering application in the design of hypersonic aircrafts.This thesis is aimed at developing methods, especially at developing the computer program which is efficient and effective, to calculate aerodynamic heating distributions for the hypersonic aircrafts.Main works of this thesis could be summarized as follows:Firstly, an overview of the development of hypersonic aircrafts and the necessity of studing aerothermodynamic characteristics is done. All the classic aerodynamic heating calculating methods developed by the scholars are analyzed systematically and classified.Secondly, the complex flow field characteristics of hypersonic flow are introduced. The steady hypersonic flow of air over a sphere is studied numerically using CFD-FASTRAN softwares. This case considers complex thermodynamic behaviour such as vibrational and chemical nonequilibrium. And CFD results such as the shock stand-off distance, heating rates agree well with the corresponding experimental data.Thirdly, more efficient and effective engineering methods for calculating aerodynamic heating rates are studied in this thesis. The engineering estimation method contains a detailed description of the theoretical approach and the simplified formulas for aerodynamic heating rates solution to the problem. The code is based on the axisymmetric analogue which need track the inviscid surface streamlines.The boundary layer edge conditions are determined by using CFD method to solve Euler equations or using the modified Newton theory and other equations. Then a fortran computer program is developed which calculates laminar and turbulent heating rates on arbitrary blunt-nosed three dimensional bodies at an angle of attack in hypersonic flows.By comparison with experimental data for a blunted 15 half-angle cone and a bent-nose biconic, the method is found to yield reasonably accurate laminar heating rates for these cases, improves the calculational accuracy than using some engineering codes and consumes less calculational time than solving Navier-Stokes equations in entire flowfield. It is a reasonable choice to predict heating rates for complex vehicle configurations in an entire trajectory and in the initial design phase.In short, the methods studied in this thesis are complementary and mutual authentication. Different design phases of the hypersonic vehicle can be focused to choose a different calculation methods. The results of these tools should be combined together and made a comprehensive analysis to solve the problem.