Research On Key Technologies For Digtial Model Reconstruction Of Turbine Blades Faced Product Innovation Re-design

Turbine machinery plays a very important role in the national economy.As the core component of energy conversion,the design of the turbine is very complicated,while the design process of turbine blade which is a typical type of sculpture surface parts involves very complicated multidisciplinary theory and technology.In addition,the process needs going through the aerodynamics test,it will inevitably results in a long development cycle and a high cost.Therefore,it is very necessary to use reverse engineering technology to carry on the corresponding modification design and innovation basis on the existing model,certainly it will greatly shorten the development cycle and reducted the cost of new products.With the development of RE,its industry applications for common parts are quite consummate.So notable efforts have been made toward CAD model Reconstruction on complex products with high quality and efficiency.Furthermore,in order to meet the requirement of rapid new.product development in the times of economy globalization,Based on the physical product,recovering original design intent and supporting product innovation design are highly regarded as the research emphasis of CAD modeling methodology in reverse engineering.So in this article,Turbine blade is taken as research object based on developed feature modeling technology in reverse engineering,Key technologies for CAD model reconstruction of turbine blades faced product innovation design are intensively explored in this dissertation.The methodology that the pressure side&suction side points described by quintic polynomial curves using Matlab software and the trailing edge&the leading edge defined by arc,that tenon's section points fitted by lines and arcs were presented.The characteristic parameters of blade and the geometry parameters of tenon cross section were presented.It is helpful and valuable to enrich CAD modeling theory and improve technologies of CAD model reconstruction in reverse engineering.CAD model,which supports innovation of product design and the reconstruction of design intent restoration.The main research works and results in this paper are summed up as follows:(1)Aiming at the requirement of rapid new product development,the system frame of CAD model reconstruction of turbine blades faced product innovation design is founded.The basic target and requirement of CAD model reconstruction faced product innovation design are comprehensively and systematically summarized;Point cloud density estimation method is presented;and the curve surface fitting,the key technologies of cross section point cloud data acquisition and the cross section line reconstruction are detailedly discussed;The reasons of error in reverse engineering are analyzed and the importance of reduction product original design parameters is pointed out.(2)Based on classification and conclusion of existing physical measurement techniques,the advantages and disadvantages of CMM(Coordinate Measuring Machine)and the Handyscan,measurement technique and system composition of Handyscan,general process of point cloud data's acquisition are detailly analysised.Aimed at the blade products with complex shape,the point cloud data acquisition method used laser scanner is put forward.The reasonable point cloud of turbine blades is finally realized.(3)According to the characteristics of the turbine blade point cloud data,extracting outliers,smoothing filter and repairing are discussed in detail,the point cloud data and method of point cloud data;The method of date reduction with curvature sampling,chord deviation sampling and equidistant sampling in turn is presented in this paper.(4)The methodology that the blade profiles described by quintic polynomial curves using Matlab software and the trailing edge&the leading edge defined by arc,that tenon's section points fitted by lines and arcs were presented,which supports product design intent and parameters restoration.The method based on characteristics and constraints of extracting geometric feature parameters is pointed out.(5)During the process of CAD model reconstruction of Turbine Blade,the methodology Combined with based on feature-based and freeform-based CAD model reconstruction,cross section-based and surface-based surface reconstruction,key research turbine blade reverse modeling,curve/surface characteristics form expression and NURBS form expression is presented.Positioning,division and turbine blade's surface reconstruction of point cloud are emphatically analyzed.the laser scanning The complete process from point cloud data obtained by handyscan to CAD model meeting design requirements is realized.As stated above,CAD model reconstruction of turbine blades faced product innovation design is proposed to improve the theory of CAD model reconstruction,is helpful and valuable to develop technologies of CAD model reconstruction in reverse engineering.