International Cavitation Erosion Test and quantitative assessment of material resistance to cavitation

In September 1987, during the ELSI VII Conference, the start of the International Cavitation Erosion Test (ICET) project was announced. The experimental programme consisted in testing 6 selected materials (single-phase aluminium and brass alloys, Armco iron, carbon and chromium-nickel steel, and a polyamide 6 plastics) at various laboratory rigs. Tests were conducted at 4 cavitation tunnels, 4 rotating disks, 6 vibratory rigs, 1 liquid jet and 2 cavitating jet facilities. The results, now available in form of a MS Access database and the ICET Preliminary Report, convince that in addition to standardisation of selected experimental techniques, one should strive to develop methods allowing to predict material performance under variable cavitation loading conditions. in the present contribution, a method of quantitative material resistance assessment based on an idea of defining response to individual fractions of cavitation pulses histograms is proposed. Cavitation pulses are classified as micro- and macro pulses, depending on the affected area size, and divided into amplitude fractions. Erosion due to individual fractions is assumed to follow the same general law Delta V = A . MEi .U(k(i),E) with A the eroded area, MEi the power flux delivered to a unit area of impinged surface, E the cumulative energy delivered to this area, and k(i) the material resistance vector consisting of parameters of the erosion progress function U. The erosion progress due to the polyfractional cavitation impingement is assumed to follow a superposition law described by a differential equation presented in the paper. Advantages and weakpoints of the approach are discussed. (C) 1999 Elsevier Science S.A. All rights reserved.