PREDICTION OF CAVITATION ON KAPLAN TURBINES USING FUZZY LOGIC MODELLING

Abstract

Cavitation is a serious problem causes surface erosion in hydraulic turbines as a result of evaporation and condensation of water due to pressure change, it typically causes noise, vibration and finally limits the operating range of the turbine, The present paper deals with a numerical method for prediction of cavitation damage level on Kaplan turbines. A method was applied to predict the intensity of cavitation damage to using the Fuzzy Logic System. Five levels of damage intensity were considered to predict cavitation damage in the Kaplan turbines of Rosaries Dam in Sudan. According to the results, the proposed model could properly predict the intensity of cavitation damage in comparison with the actual reports in the past critical periods, flood season, water restriction and black out times. The fuzzy logic (Mamadani system) is applied with aid of MATLAB in three input cases, first is for cavitation index only, second is for flow velocity only, and finally is the combination of both cavitation index and flow velocity governed by 25 (AND) intersection rules. Two output results could be gained into two formats one is a (2D) rule viewer and the other is (3D) surface viewer from which a decision making can be taken after converting the output linguistic terms into crisp, efficient and suitable values.