A liquid jet upon atomization breaks up into droplets that are orders of magnitude smaller than its diameter. And the multiscale simulation is a good idea to use different models at different scales. A new multiscale simulation method of primary atomization is proposed. The liquid blobs much larger than the cell volume are captured by Volume-of-Fluid (VOF) method, while the droplets comparable with the cell volume or less are tracked by a two-way coupling Lagrangian Particle Tracking (LPT) model. If the LPT droplets impact the liquid blobs, they will be transformed back to VOF-resolved field properly, avoiding the liquid droplets moving in the liquid blobs. A new LPT algorithm upon a virtual mesh is presented to satisfy the requirement that the particle volume must be less than 10% of the Lagrangian cell volume. Large Eddy Simulation (LES) is used to describe the turbulent flow. Then a new code is developed and validated. Some characteristic parameters, such as transforming limits between VOF field and Lagrangian particles, momentum allocating coefficients, and so on, are investigated. Finally, the impinging injectors with different structures and operating parameters are simulated, emphasizing on the impingement angles and momentum ratios of the two jets. The instantaneous and time-averaged properties of the two jets agree well with experimental results.
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