Large Eddy Simulation of Primary Diesel Spray Atomization

One of the major problems in the CFD simulation of Diesel sprays is the incomplete and inadequate specification of initial conditions for the spray droplets. This is mainly a consequence of lack of understanding of the atomization process, which has inhibited the development of sufficiently general and accurate models for use in engine combustion simulations. In this paper a novel CFD approach, combining multiphase volume-of-fluid (VOF) and large eddy simulation (LES) methodologies, is used to perform quasi-direct transient fully three dimensional calculations of the atomization of a high-pressure diesel jet, providing detailed information on the processes and structures in the near nozzle region. The methodology allows separate examination of diverse influences on the breakup process and is expected in due course to provide a detailed picture of the mechanisms that govern the spray formation. It will therefore be a powerful tool for assisting in the development of accurate atomization models for practical applications. Our investigations so far have focused on the performance and initial validation of the methodology, in the absence of cavitation.