Manolis Gavaises (City University London) - Modelling of bubble dynamics, cavitation and their effect on near-nozzle spray formation

Methodologies for simulating cavitating flows are presented and assessed against available experimental data. Initially, an explicit density-based solver of the compressible Euler equations suitable for cavitation simulations is presented, using the full Helmholtz energy Equation of State (EoS). Tabulated data are derived from this EoS in order to calculate the thermodynamic properties of the liquid, vapour and mixture composition during cavitation. That allows prediction of the temperature variation of both the liquid and the vapour phases. As a follow-up, physical properties data and VLE are also predicted using the PC-SAFT EoS for hydrocarbon fuel mixtures covering a wide range of P-T conditions. This allows simulation of bubble/bubble cluster collapses at conditions relevant to those prevailing in fuel injectors; incorporation of grid motion techniques allows simulation of cavitation in complex geometries, aiming to indicate location prone to cavitation erosion. Simplifications to the thermodynamic closure model through a 3-phase barotropic model allows further application of the model to problems of increasing engineering complexity; cases considered include the effect of cavitation on the atomization of liquid sprays during the transient opening/closing of the needle valve and the simulation of cavitation during the impact of a projectile on a water jet.