STUDY OF CAVITATION EROSION RESISTANCE OF DIFFERENT TURBINE BLADE MATERIAL USING ASTM G 32

Abstract

This project presents a detailed study of cavitation erosion resistance of turbine blade material (13Cr4Ni) with the help of cavitation erosion testing method ASTM G32 which is oldest commonly used in the laboratory. The ultrasonic technique and the liquid jet technique both are two most popular laboratory techniques for testing cavitation erosion characteristics of materials. The vibratory cavitation apparatus (G32) is available with its two variants, the Direct method using a specimen attached to the vibrating tip of the ultrasonic horn and the alternative method using a fixed Specimen facing the horn tip (Indirect method).In this project all the readings as well as results are taken with the indirect method in which a fixed specimen placed at some distance from the vibratory tip and the specimen is facing the tip of the horn. Cavitation is well known problem in the field of hydropower plant and industries. Cavitation cause a heavy material loss in running hydropower plant which will ultimately increase the cost of maintenance and as a result of which total cost of project will increases. Proper evaluation of new materials for their resistance to cavitation erosion requires a comprehensive effort addressing both the intensity of the cavitation field and the resistance of the material. In the absence of historical data on the performance of a new material in the target cavitating flow fields, experimental studies in the laboratory offer a convenient means of assessing the cavitation erosion performance. Usual testing procedures together with typical erosion patterns and mass loss results obtained in such facilities are also presented.