SCALE EFFECTS ON LIMITED CAVITATION PRODUCED BY VIBRATION OF THE WETTED SURFACE OF CYLINDER LINERS

The processes of cavitation erosion in the space within the cylinder jacket of Diesel engines, which is the principal cause of failure of the outer wetted surface of cylinder liners, can be suppressed by avoiding the appearance of cavitation. This can be achieved if reliable information existed about the scale effects on the inception of cavitation which are an important consideration in the prediction of inception in a design process. Unfortunately there is insufficient information available at present to help the engine designer. Therefore, the purpose of this paper is two-fold. First, new experimental data are presented which show the effects of the vibration frequency, water distance, and water temperature and pressure on the inception of cavitation. Second, a model for the inception of cavitation is presented. Cavitation inception data are presented and discussed for a vibratory setup. The vibratory setup was designed to simulate the flow on the wetted surface of a liner. Measurements of inception were obtained visually through a transparent beaker containing tap weter. The effects of vibration frequency, water depth, static pressure of water and water temperature on the inception of cavitation were investigated. The results showed that the cavitation inception vibration amplitude decreased with increasing the vibration frequency and the temperature of water. In addition, the cavitation inception vibration amplitude increased as the depth of water increased. The results were compared with the model and a good agreement was observed. In the light of these results the designer should design his engine with cylinder liner vibration amplitude less than the inception vibration amplitude to operate his engine free of cavitation and therefore to avoid damage due to Cavitation.