Multiscale modeling of turbulent atomization: Droplet-size sampling

Abstract

With an interest on atomization in turbulent flows, and modeling alternatives to classic atomization models and Direct Numerical Simulations (DNS), the present work derives and tests two droplet-size distributions parametrized by local information about the flow. One distribution is heuristic and another one is based on the linear-eddy model. Predictions from these distributions are tested with numerical simulations in which the unresolved droplet-mass production is closed by assuming that turbulence is the rate controlling mechanism and by using a correction step. Moreover, the testing considers a round jet with a Reynolds number of 5000 from which DNS data is available. Overall, it is found that the present atomization model provides an enhancement of accuracy of the droplet-mass production and droplet-diameter distribution in comparison with using no model. Furthermore, the predicted droplet-diameter distribution is more accurate than that using a previous assumption of taking droplet diameters equal to local Taylor microscales. These results are obtained with simulations whose cost is orders of magnitude less than DNS.