3D solid modeling method of Francis turbine blade based on UG

In this paper, 3D solid modeling method of Francis turbine blade is researched. Based on powerful capacity of materializing surface of UG NX 4.0 and the data of original wooden patterns, the blade spline modeling was established by NURBS，and the blade space surface was constructed. Meanwhile making a mathematical analysis for the free surface extension of Francis turbine blades and proposing new solutions. A good result of Smoothness test for runner blades shows that the solid modeling method is feasible. 3D solid model lays possibility for analysis and CNC machining of follow-up blades.