汽轮机静叶片内背弧型线优化设计与研究

The Research and Optimization Design of the Inner and Back Arc Profile Line for the Steam Turbine Static Blade

汽轮机静叶片装配内背弧型面的加工是汽轮机静叶片关键工序之一。针对汽轮机静叶片内背弧型面的型线结构与加工特点,应用三次样条曲线、多项式插值曲线拟合内背弧型线,以内背弧型线的原始数据为基础,进行数值计算得出拟合后的型值点,从而得出拟合型线。通过拟合误差分析结果表明:相对于模糊的NURBS曲线形式,拟合后的型线确定为三次样条曲线(C3型),且具有较小的轮廓误差,保证了设计时零件的精度及表面粗糙要求,同时型线具有良好的光滑性、连续性。

The back curved surface machining of the steam turbine static blade is one of the key processes of the steam turbine static blade. For researching the structural characteristics of the inner and back arc profile line and the WEDM-HS processing of the steam turbine static blade, it uses the polynomial interpolation curve and cubic spline curve to fit the inner and back arc profde line, which is based on the original datca Then it obtains the fitting data points form numerical calculation, so that the profile line is got. From the fitting error analysis, the result show that： relative to the form of fuzzy NURBS curves, after the fitting, the inner and back arc profile line fitting is identified as cubic spline curve （C3 type） ,which has the smaller contour error. It guarantees the requirements of the part accuracy and surface roughness, at the same time makes the optimization designed profile line more smoothness and continuity.