Research On Airframe/Inlet Integrated Waverider Aerodynamic Design Technology Of Air-breathing Hypersonic Vehicles

The reusable hypersonic aircraft based on TBCC engine is one of the most important research hotspots.And the design method of forebody-inlet integration plays a critical role on aerodynamic configuration.However,the studies on the airframe-inlet integration of air-breathing hypersonic vehicle are few at present,and basically do not involve the wide-speed factor.Therefore,this thesis focuses on the technologies of airframe-inlet integration for TBCC hypersonic aircraft,and provides a set of accurate and reliable aerodynamic design methods which can improve the engineering practical value of hypersonic vehicle.In this research,the present design methods of hypersonic aircraft focused on forebody-inlet waverider are systematically summarized.For the first time,the existing methods are innovatively classified by the construction of generating flowfield,which are respectively based on the controllable geometric parameter of generating body,the controllable boundary pressure distribution,the controllable boundary Mach number,the controllable leading shock wave and the controllable multiparameter combination.Then,the categories of the waverider applied to hypersonic aerodynamic configuration are classified and summarized.The design methodology of multistage compression waverider based on inverse method of characteristics(MOC)is researched.Firstly,the theory of MOC is demonstrated,which contains the derivation processes of control equations,characteristic equations and compatibility equations.The numerical solution process of the four typical characteristic units applied in this paper is elaborated,namely the interior unit,the direct wall unit,the inverse wall unit and the inverse interior unit.Then,the design method of multistage compression cone-derived waverider based on the inverse MOC is proposed.Two procedures are introduced in detail,that the calculation of affected flowfield derived from initial boundary of leading shock wave and the process of accurately tracing streamline.And the generating flowfield with multistage compression shock waves is constructed by inverse MOC and the method of extending shock wave.Furthermore,the theory of inverse MOC and the design method of multistage compression waverider are validated by numerical simulations and analysis of aerodynamic performances.At last,a contrast with the traditional method of multistage compression waverider based on Taylor-Maccoll equation is executed.Aiming at the shortcomings of the traditional multistage waverider based on Taylor-Maccoll equations which has large error and only can generate flowfield with linear shock waves,the design method of multistage compression waverider with curved shock waves based on inverse MOC is further developed.Firstly,the basic principle of the new method is introduced,which parameterizes the multistage curved shock waves with the power function and the Bezier function.In order to correct the physical singularity problem caused by the power-function shock wave,this paper adopts two methods of adding linear equation and offsetting the origin to solve it.For the different initial constraints,two generating processes of equiaxial curved-shock waverider and equilong curved-shock waverider are respectively introduced.Then,the influences on the multistage waverider derived from different shapes of convex,linear and concave shock waves are compared,and the influences derived from different stages of shock waves are also compared to analyze the aerodynamic performances.At last,the method of multistage osculating cone-derived waverider based on inverse MOC is further proposed and compared with the one of pure cone-derived waverider.Based on the MOC,the improved integration method of multistage compression waverider and truncated Busemann inlet is proposed for the first time in this thesis,which combines the advantages of both and avoids their shortcomings.Firstly,the traditional integration method based on Taylor-Maccoll equation is introduced,and it has large error on the construction of complex generating flowfield.In order to correct the traditional problems,the new method based on the MOC is presented.The critical procedure is the construction of the forebody-inlet generating flowfield which contains multistage compression zone,truncated Busemann compression zone,the dependent zone of reflected shock wave at inlet entrance and the free-flow zone of the isolator.Then,the new method is validated by numerical simulations and the numerical error of the free flow at isolator is analyzed and explained.Compared to the simple multistage compression waverider,the new method has better precision and performance.Furthermore,considering the interference of the viscous boundary layer,the von Karman momentum equation integration method is used to correct the displacement thickness of the boundary layer on the basis of the MOC,which further reduces the overflow at inlet entrance and the flow choking at isolator.At last,a sensitivity analysis of several key design parameters for the truncated Busemann inlet is executed.The strategic hypersonic vehicles based on TBCC power has wide flight speed and large airspace.Its flight speed ranges from low subsonic Mach number at the time of takeoff and landing to hypersonic Mach number during cruising,and its airspace ranges from the ground to the adjacent space.Base on the integration method of multistage waverider and truncated Busemann inlet as mentioned above and combined with ‘full-waverider’ design philosophy,the forebody-inlet-airframe integration method with variable angle of shock wave based on osculating flowfield is proposed for the first time.Firstly,the design theory based on the MOC of the new integration method and the constructing process of the osculating ‘full-waverider’ generating flowfield are introduced in detail.Secondly,with keeping the‘full-waverider’ property at cruising time,a variable Bezier law of shock wave angle is applied to design the parameterized strake wing,which takes consideration of the low subsonic performance.Thirdly,the osculating ‘full-waverider’ integration method with variable angle of shock wave is compared with the one with constant angle of shock wave by the numerical simulation,the results validate the correctness and excellence of the novel method proposed in this thesis.Fourthly,with the aim for wide-speed and horizontal take-off hypersonic aircraft based on TBCC power,the ‘full-waverider’ integration method with ventral intake is developed to a new integration with two lateral intakes.The new method increases the design freedom of the intake capability and the practical applicability for engineering request.At last,on the basis of aforementioned methods,the whole forebody-inlet integration and the dependent regions of the leading shock waves at outer airframe are strictly retained,and a final project of widespeed hypersonic aircraft based on TBCC power is preliminarily presented.It should be noted that the final project does not involve the aerodynamic optimization and design technology of the ramjet nozzle and combustion chamber.It is only an application form for the set of design techniques in this thesis.Finally,the main research contents and innovation points of the thesis are summarized,and the subsequent development of design techniques is prospected.