BUBBLE DYNAMICS MODEL FOR PREDICTING THE GROWTH AND COLLAPSE OF CAVITATION BUBBLES IN DIESEL INJECTOR

摘要

This paper investigates the applicability of the existing bubble dynamics models, i.e., the Rayleigh Plesset (RP) equation and the simplified RP, which is called the Rayleigh (R) equation in the following, to the prediction of the growth and collapse of cavitation bubbles in a diesel fuel injector. We propose the modified Rayleigh (MR) equation, which improves drawbacks of the former models. The agreement between calculated and measured bubble radii confirmed the validity of the RP equation. Numerical calculations are performed for various cases, such as a water injection at low injection pressure and a diesel fuel injection at high injection pressure. The proposed MR equation is confirmed to satisfy (i) low computational cost by using a large time step, (ii) avoiding a large numerical error using large time steps, and (iii) good estimations of the growth and collapse rates of cavitation bubbles under various pressure conditions.