Automatic Modeling Techniques Research Of Integral Impeller Based On UG

The design requirements of the integral impeller who is an important part ofthe aerospace engines must comply with the principles of fluid dynamics. Whenmodeling for the impeller, the designer only provides some of the discrete datapoints, if modeling through these data points, the quality and fairing degrees ofthe model would be bad, which directly affects the the using performance of theNC machining process and the finished products. Therefore, it is very importantto build a integral impeller model which meets the aerodynamic requirements,whose model accuracy is high and whose surface quality smooth by studying thestructure and design characteristics of integral impeller. According to the abovereasons, this article combines the NURBS theory and knot insertion algorithm tocarry out the following studies:Firstly, according to the classification of the integral impeller, this articlestudied the structure features of each kind of the impeller. And this article in-depth studied the impeller of modeling methods. The split impeller should benoted that the leaf margin at modeling. The semi-open impeller should be notedthat non-developable ruled surface modeling. And the closed impeller should benoted that the connection of the inner and outer ring. To ensure the versatility ofthe development program, this article simplified the classification of the integralimpeller. This article mainly researched the shape of ruled blades and unstraightblades to provide technical support for subsequent software development.Secondly，this article researched B-spline and NURBS theory and itsinterpolation algorithm, and Boehm algorithm and node universal interpolationalgorithm are applied to the NURBS curve modeling. New control node isinserted in the blade section online. So then this article achieved remodeling andfine-tuning, and building NURBS blade surfaces which provided a theoreticalbasis for the development of the CAD system.Thirdly，this article achieved the CAD modeling system based on UG platform by Grip language. This article built a data point of the section line re-distribution by the chord tolerance, which achieved automatic modeling of threeintegral impeller geometrically and optimized the model. At the same time thisarticle developed the surface analysis module to verify the accuracy of the model.Finally, this article researched the generated factors of the model error, builtthe quality rating system, accomplished the comparative analysis of the originaldata model and the CAD model deviation, and detected curve curvature and thesurface fairing degrees, This article analyzed the quality of the model built by theCAD system developed in this paper through surface analysis methods, theevaluation model and evaluated the quality of the model.