Accurate And Rapid Method Of Aircraft Aero-force&Aero-heating Calculation And Research On Applications

The aerodynamic design optimization is an important part of the design process of aircraft.The key points of aerodynamic design optimization is accurate and rapid calculation of aero-force & aero-heating,and high-efficiency global optimization algorithm.In this paper,accurate and rapid method of aircraft aero-force & aero-heating calculation,and Sequential approximation optimization method were studied.An accurate and rapid method of aircraft aero-force calculation is studied.The flow fields are divided into turbulence control region,laminar flow control region and inviscid flow control region,then Favre averaged Navier-Stokes(N-S)equations,laminar N-S equations and Euler equations are taken as flow governing equations for the different region respectively.Which greatly reduces the complexity of the flow control equations.Based on the known steady flow-field,a new flow-field initialization method for steady flow numerical simulation around an aircraft is proposed.The computational stability of the flow-field numerical solution process is improved and the convergence rate is accelerated.A high-efficiency and general-purpose method for calculating the outer boundary of the computational domain around the aircraft is proposed,which minimizes the computational domain and mesh notably.In this paper,the complexity of numerical simulation problem of steady flow around aircraft is greatly reduced,without affecting the description accuracy of physical problem,and the numerical simulation efficiency is greatly improved.The proposed method is verified by wind tunnel test data,and the calculation precision meets the requirement of engineering design.An accurate and rapid method of aircraft aero-heating calculation is studied.The aero-heating calculation model of aircrafts was established based on the axisymmetric analog method.The calculation model of the outer boundary layer parameters of the aircrafts is established.The mathematic relationship between the streamline metric coefficient,flow parameters and geometric parameters was established.The method of solving the streamline metric coefficient explicitly is proposed,the complex streamline solving problem is avoided and the solution efficiency is improved effectively.The method of solving the aero-heating characteristics of aircrafts is built up.The wind tunnel test data are used to verify the method,and the calculation precision meets the requirement of engineering design.The improved sequential approximation optimization method is studied profoundly.The Design of Experiment(DOE)method based on quasi-random sequential is proposed.The acceptance criteria and steps of the DOE process are established.The method has a small computational cost and generating good distribution sample points.An analytic determination method of the kernel width of Gaussian radial basis function based on the local density of the sample points is established,which avoids bringing new calculation amount,and obtains an efficient,reliable and high precision approximate modeling method.A new multi-stage adaptive sampling point updating method is proposed,which consists of three stages: potentially feasible regions locating,exploring in the potentially feasible regions,and potential optimal sampling.The sampling process restrains the distance between the new sampling point and the existing sampling points through the adaptive distance constraint function.And the stop criterion of each sampling stage is established based on the approximate model precision.An improved sequential approximation optimization method is established.The typical cases study results show that the proposed method is an efficient and reliable global optimization method,which can significantly reduce calls of the original model,and is suitable for solving the optimal design problem based on complex model.The application of the accurate and rapid method of aircraft aero-force & aero-heating calculation is studied in the solid launch rocket shape optimization process.Initial shape and trajectory of the solid rocket is demonstrated,the momentum loss caused by the aerodynamic drag along the trajectory is taken as the objective function for the optimization of the fairing.The aerodynamic shape optimization of the fairing is completed.The optimization result satisfies the design constraint.The objective function is 11.7% less than the baseline.On the basis of optimizing the shape of the fairing,the optimization of the grid fin shape is completed.The result of optimization satisfies the requirement of design constraints,which can increase the carrying capacity of the rocket effectively.In this paper,the accurate and rapid method of aircraft aero-force & aero-heating calculation are studied profoundly,and the method of approximate sequential optimization is studied.The method has good adaptability to the aerodynamic design of complex aircrafts.And the proposed methods can be applied to the design optimization of other types of aircraft.