Experimental And Theoretical Investigation Into Rock Erosion Of Cavitating Water Jets

With the application of cavitating water jets in mine engineering, petroleum engineering and rock cut, the theory of cavitating water jets rock erosion is still not unified.Referring to Science Fund for Creative Research Groups(50621403), a series of experiments relating to erosion rock of cavitating water jets were carried out .With fluent software and CT testing, not only experiment datum for cavitating water jets erosion rock will be highlighted, but also their contributions towards erosion mechanism of cavitating water jets will be revealed.The main conclusions of the paper are showed as follows:①The relation between cavitating water jets erosion effect(erosion mass, erosion depth) and pump pressure or cell pressure is conic. The erosion effect increase with pump pressure,while it reduce with cell pressure. It is concluded that cavitation is the main factor of cavitating water jets erosion rock .②By comparing several turbulent models, standard k -εmodel , renormalisation -group (RNG) k -εmodel, realizable k -εmodel, standard k -ωmodel, shear stress transport (SST) k -ωmodel, it can be concluded that the RNG k -εmodel predicts more realistic results than the other models used in the simulations. The RNG k -εmodels successfully predicted the potential core (constant velocity for a distance) and the best standoff distance. The simulated values and experiment result are validated each other.③Using PCI-2 acoustic emission System and CD-300BXR indestry CT machine test the sandstone samples, which have done the cavitating water jets erosion rock experiment. The result reveal that the efficiency of a cavitating water jet is very well and the erosion rock can be measured off three parts, erosion cavum,cranny area (damage area) and none effected area. The efficiency of cavitating water jets erosion rock depends on the rock character.④Limestone can not be erosion by cavitating water jets on the condition of the most pump pressure, but sandstone were greatly erosion. At present cavitation erosion theory, such as chemistry erosion theory, electrochemistry theory, heat action theory, can not explain this phenomena. The research on rock crack combining machine action theory was made. The main innovation of the dissertation is that finding the best models used in the simulations is the RNG k -εmodel which predicts more realistic results than the other models, and erosion mechanism of cavitating water jets were revealed by using 8CHS PCI-2 acoustic emission System and CD-300BXR indestry CT machine. These have great theoretical and practical guide value to consummate rock erosion of cavitating water jets theory.