Abstract: The selection of hydraulic turbines for a power station and the same kind of product designs depend on the performance curves of a turbine model. The curves are provided in graphs. During of the optimum design of a power station, various kinds of characters in the graphs need to be expressed in mathematic methods so as to design automatically. At present, they are read out by human and input into computer so that we have a great deal of work to do and errors are often let to. It is difficult to be satisfied for modern designs, therefore, the characteristic pa-rameters in graphs are automatically gotten by the clicking of a mouse, curves are fitted with higher accuracy so as to design automatically and an arrangement record method in their drawing order is established. They can quickly deal with a large number of supplied performance curve for model turbines to meet the needs of modern individualization. In addition, the method is also suitable for the data collection of other kinds of pictures.

Key words: Numerical simulation, Characteristic curve, Computer-aided data collection, Operation curve