Research On Surface Reconstruction Method Of Three-dimensional Aircraft Icing

Aircraft icing seriously affects flight safety.The numerical simulation method has become the main method for icing research due to its unique advantages.During the numerical simulation of three-dimensional aircraft icing,the multi-time step method can more accurately simulate the actual aircraft icing.In this thesis,the NURBS surface reconstruction method is used to develop a three-dimensional surface reconstruction algorithm for aircraft icing by programming.The numerical simulation of three-dimensional multi-time step icing is realized by using this algorithm.This article focuses on the following:Firstly,this paper introduces the flow field calculation,water droplet trajectory calculation and icing calculation in the three-dimensional icing numerical simulation.The governing equations of each part and their solving methods are described respectively.The rationality of these algorithm are verified by comparing the calculated results with the experimental results.At the same time,we also introduce the method of multi-time steps numerical simulation and the problems they face.Then,based on NURBS surface reconstruction method,a three-dimensional ice-shaped surface reconstruction algorithm is developed.Based on the wing data structure,a data retrieval algorithm is also developed to establish a new topological relationship of surface nodes.The basic concepts of B-spline surface,node type and surface reconstruction are introduced.An algorithm process for surface reconstruction is designed to realize the transformation from nodes to surface.The IGES format is uesd to realize the transformation from surface to solid.An ice-shaped surface reconstruction example verifies the correctness of the reconstruction algorithm.Finally,the algorithm is used to simulate the multi-time icing numerical simulation of various three-dimensional wing segments under different icing weather conditions.The results show that the multi-time step calculation result is closer to the experimental result than the single time step,which verifies the correctness of the numerical simulation method and the surface reconstruction algorithm used in this paper.And it also illustrates the advantages of multi-time step in the icing numerical simulation method.Besides,this paper study a optimal time step for numerical simulation of three-dimensional icing.The variation of the water collection coefficient with time is analyzed.The law of rising resistance and pressure cloud with time are also analyzed.