THE LAWS OF CAVITATION EROSION OF CONSTRUCTION MATERIALS

Abstract

Objectives . The aim of the research is to find ways to use cavitation effects in the creation of new technologies and means of applying unique opportunities arising under conditions of developed bubble cavitation. Erosive destruction of concrete caused by a submerged cavitation jet is experimentally investigated in the present work in order to reveal the regularities of the extent of damage under different flow regimes. Methods. The tests were carried out using an specially constructed experimental bench, containing a receiving tank from which water was supplied to the plunger pump with an electric motor and pumped through a high-pressure hose into the cavitator. The criteria for assessing the intensity of cavitation impact were the dependence of the erosion zone depth on the test time and the relative distance to the cavitator's cut-off e for different values of the inlet pressure Po. Results. Experimental dependences and the analytical function of erosion penetration rate over time, as well as the relative distance between the sample and the cavitator's cut-off, obtained using the regression analysis method, are presented. For the selected parameters of jet flow, the optimum distance from the surface to be destroyed to the cavitator lies across the range of (10-40) e and reaches maximum effect across the pressure interval of 2.5-12.5 MPa on the average for 30 seconds. The relationship between the depth and the erosion penetration rate for given pressure parameters P0, the back pressure Pto, the distance from the cavitator's cut-off to the surface, as well as the cavitator's diameter, correspond to the maximum erosive effect of cavitation. Conclusion. The study of cavitation erosion opens up wide possibilities for estimating the service life of hydrotechnical facilities under the active influence of submerged cavitation jets. By varying the parameters of jet flow, it is possible to obtain a different intensity of erosive destruction of material for the application of this phenomenon in the purification and crushing of concrete.