Present trends in protection of hydraulic turbines against cavitation pitting

Abstract

1. The most important a pproach for increasing the wear resistance of hydraulic turbines against cavitation is the development of hydrodynamic means for controlling the cavitation and reducing its pitting capacity. Of great significance is the development of cavitation-resistant materials and coatings and of techniques for applying them. The electrochemical means for protection against cavitation have not yet been sufficiently developed for extensive use. It is convenient to organize laboratory investigations on cathodic protection and methodical testing of this type of protection in one or two small turbines. 2. An important method of preventing cavitation pitting is the proper selection of the operating regimens. At the present time, methods have been worked out for predicting the intensity of cavitation action under different operating regimens of the turbines, on the basis of analytical data about the pressure distribution. The relative pitting hazard can be tentatively evaluated from the intensity of recorded acoustic radiations.