Continuous curvature airfoil based on four-segment rational bézier curves and its generation method

Abstract

The invention discloses a continuous-curvature airfoil profile represented on the basis of four rational Bezier curves, and a generation method for the continuous-curvature airfoil profile. The front edge portion of an upper molded line and the tail edge portion of the upper molded line are represented by two rational Bezier curves, the front edge portion of a lower molded line and the tail edge portion of the lower molded line are represented by the other two rational Bezier curves, and the four rational Bezier curves are sequentially connected by adjusting the positions and the weights of control vertexes near the splicing points so that the continuous-curvature airfoil profile can be generated. Parameters in a function have clear geometrical significance, the expected airfoil profile or an expected airfoil profile family can be generated by adjusting parameter values, the curvature radius of the front edge of the airfoil profile can be controlled, the position and the curvature of the highest point of the upper molded line are matched with those of the tail portion of the airfoil profile so that the closed airfoil profile with the thick tail edge can be generated, and reverse design is achieved; the four rational Bezier curves are made to approach an existing airfoil profile by adjusting the parameter values, and therefore approximate expression of the existing airfoil profile can be obtained, and the continuous-curvature airfoil profile can be applied to forward direction aerodynamic optimization design.

Description

technical field [0001] The present invention relates to a blade or wing of a turbomachinery and a manufacturing method thereof, in particular to an airfoil of a blade or a wing and a method for producing the same Background technique [0002] At present, the airfoil profile of a blade or wing is generally determined by a coordinate database, that is, a series of coordinate data is given, and then the image lattices represented by the data are connected in sequence with smooth curves to generate the airfoil profile. There are many deficiencies in the profile generated by this method: (1) the generated profile cannot guarantee the overall continuity of the curvature; (2) the number of parameters in the profile expression is generally large, and there is no clear geometric meaning, And when the parameter value changes, the image will change unpredictablely, and even the shape of the airfoil cannot be expressed; (3) it is difficult to connect the data of various types of airfoil...

AI Technical Summary

Problems solved by technology

There are many deficiencies in the profile generated by this method: (1) the generated profile cannot guarantee the overall continuity of the curvature; (2) the number of parameters in the profile expression is generally large, and there is no clear geometric meaning, And when the parameter value changes, the image will change unpredictablely, and even the shape of the airfoil cannot be expressed; (3) it is difficult to connect the data of various types of airfoils with the same smooth curve; (4) the An airfoil line can only represent an airfoil, not an airfoil family

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