混流式水轮机叶片设计与木模图的数值实现

Numerical realization of Francis turbine blade design and wooden patterns

针对传统的混流式水轮机转轮叶片设计方法(如保角变换法)设计周期较长,且不易实现叶片模型制作的状况,通过给定速度矩方程对叶型骨线方程进行逐点积分,并由包角的误差分析对速度矩方程的系数进行修正,实现叶片正面型线的设计,在叶片正面计算流面上使用导出的最大流面厚度公式直接进行叶型加厚,得到水轮机叶片的背面叶型.文中同时给出了各部分的数学分析数值计算表达式,并用CAD系统进行叶片木模图的绘形.从得到的木模图可以看出,用该方法设计更为优化,能较好地体现设计要求,并符合实际转轮叶片的形状,确保了计算和造型的准确性,可用来进一步实现水轮机的整体水力性能分析.由于模型是数值生成,故结合相应的机械加工程序,可实现叶片木模的数控加工.

In the design of Francis turbine runner blade, with the traditional method such as conformal transformation, the design period is quite long and the blade model making is very difficult. In this study the design of the turbine runner blade is improved by integrating the blade mean camberline equation, thickening the blades along the blade mean camberline in flow surface calculation and using the CAD system to draft the wooden patterns of the turbine runner blade. From the wooden patterns it shows that this design method is more optimized and meets the requirement of design better. The shape of runner blade is conformed to the practical one well. It can be used to analyze the the performance of Francis turbine, and to make the wooden patterns machining easier in using programs of numerical controlled machining.