| In view of intricate interactions between the aerodynamic,propulsion and control system of air-breathing hypersonic vehicles,it is vitally necessary for the integrated overall design and control characteristic analysis to study the model of aerodynamic/propulsion integrated theory.At present,the integrated aerodynamic/propulsion models mainly consist of such as numerical simulation of higher accuracy but time-consuming,engineering calculation of lower precision but higher computational speed and agent approximation model not suitable for study on the mechanism.The engineering calculation models of aero-propulsion integration taking account of both the precision and speed are developed for integrated overall design and the analysis and comprehensive of flight dynamics coupling characteristic,including propulsion system performance constraints of the mode conversion,overflow,isolator-cumbustor matching characteristic,optimum design-oriented air mass flux.Thus,the more accurate engineering calculation models of aero-propulsion are obtained.Lastly,integrated aerodynamic/propulsion optimum design and flight dynamics coupling characteristics are studied successfully.With regard to the above problems,based on the air-breathing hypersonic flight vehicle of waverider body configuration,the thorough and comprehensive research has been carried on by this dissertation.Firstly,based on the three conservation equations of fluid dynamics,the engineering calculation models of aero-propulsion for the integrated overall design and control characteristic analysis are brought forward.The appropriate aero-propulsion models of the air breathing hypersonic vehicle and the integral type model of quasi one dimensional flow models of propulsion system for the integrated overall design and control characteristic analysis are derived.Then comparative analysis and verification with FLUENT numerical simulation and wind tunnel tests are carried out.Secondly,scramjet performance constraints characteristics such as forebody/inlet overflow and starting,isolator-combustor matching are researched,compared,analyzed and verification with FLUENT numerical simulation except for optimum design-oriented air mass flux for the integrated overall design and control characteristics and analysis of the overall performance of propulsion system.Thirdly,based on the work of proposed aero-propulsion models and scramjet performance constraints models,the tightly integrated airframe scramjet design is carried out by means of improved selection strategy and adaptive dynamic feedback cuckoo search algorithm,the pareto optimal front is obtained,and the optimal decision scheme is given.Finally,flight dynamics coupling characteristics are more comprehensive analyzed.Aerodynamic/propulsion coupling characteristics in terms of quantitative and qualitative analysis and the contributions of the input variables to the output variables by means of variance theory and agent model are studied except for comparative analysis and verification.What's more,flight dynamics characteristics resulted from aerodynamic/propulsion coupling and the dynamics coupling measure effects between any two among the state variables,control variables and modes are researched comprehensively so as to provide a valuable reference for the design,analysis and synthesis of the control system.The contributions of this work can be summarized as follows:1)A new integral type model of quasi one dimensional flow model of propulsion system for the integrated overall design and control characteristic analysis is proposed.Based on gas dynamic functions and three conservation equations of fluid dynamics,the integral type analytic models of flow wall zone and flow separation zone are derived and then are applied to flow calculation of the quasi one dimensional flow propulsion system.The results of research have illustrated that the result parameters of the model are in good agreement with the FLUENT numerical simulation and wind tunnel tests.The calculation parameters of the model can be used to capture the main flow features,combustion chamber flow separation,combustion mode conversion and so on.The errors of axial force between the proposed model and ventilation and ignition of the wind tunnel tests are 0.89% and 6.77%,respectively.The new proposed model not only can obtain the same accuracy as the conventional quasi one dimensional flow model away from the sound velocity but also can overcome the oscillations of the conventional model in the vicinity of the velocity of sound.2)Aero-propulsion models for the integrated overall design and control characteristic analysis are further improved and studied by developing the model of scramjet performance constraints characteristics such as forebody/inlet overflow and starting,isolator-combustor matching,air flow and so on.First of all,the flow coefficient model is developed by studying the geometry of the forebody configuration,and change laws of the overflow of the forebody inlet when the mach number is lower than the mach number of design or the angle of attack is larger than the attack angle of design are revealed.Secondly,isolator-combustor matching characteristics are studied by quasi one dimensional flow calculation model based on aerodynamic function.The combustion chamber mode changing with the equivalence ratio is investigated.Finally,optimum design-oriented air mass flux characteristic model is derived by means of force analysis,energy conservation principle,specific impulse definition and so on.Inherent relationship between design air flow and fuel characteristics,design range and cruise speed is brought out.The more reasonable models for integrated aerodynamic/propulsion optimum design and flight dynamics coupling characteristics are established.3)The novel methods of aerodynamic/propulsion coupling measure and flight dynamics coupling measure are put forward and the affects of aerodynamic/propulsion coupling on flight dynamic characteristics are investigated.At first,on the basis of the variance theory and the surrogate model,a new aerodynamic/propulsion coupling measure method is proposed,the quantitative contributions of Mach number,angle of attack and equivalence ratio for the coefficients of force and moment are studied by central composite design and response surface methodology and the major factors of force and moment and its influence mechanism are determined.Then,the effects of aerodynamic/propulsion coupling on the flight dynamic characteristics of state variables and motion modes are analyzed based on time domain matrix eigenvalue perturbation theory and frequency domain analysis method.Lastly,the flight dynamics coupling measures between any two among the state variables,control variables and modes are brought forward through the analysis of zero input and zero state motion of flight state equation and the angle between vectors.The flight dynamics coupling measures among long period state variable,short period state variable,long period motion mode,short period movement mode,rudder surface and equivalent ratio(throttle) are quantitatively researched. |
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