Numerical investigation of turbulent-jet primary breakup using One-Dimensional Turbulence

Amirezza Movaghar, Mark Linne, Michael Oevermann, Falko Meiselbach, Heiko Schmidt, Alan Kerstein

Research output: Contribution to journalArticlepeer-review

Abstract

Primary breakup to form drops at liquid surfaces is an important fundamental process to study as it determines the initial properties of the dispersed phase, which affect mixing rates, secondary breakup, droplet collisions, and flow separation within the dispersed flow region. Primary breakup can be regarded as one of the least developed model components for simulating and predicting liquid jet breakup. However, it is of paramount importance in many technical applications, e.g. fuel injection in engines and spray painting. This paper presents a numerical investigation of primary breakup of a turbulent liquid jet in still air at standard conditions using the one-dimensional turbulence (ODT) modeling framework. ODT is a stochastic model that simulates turbulent flow
evolution along a notional 1D line of sight by applying instantaneous maps to
represent the effect of individual turbulent eddies on property profiles. An important feature of ODT is the resolution of all relevant scales, both temporal and spatial. The restriction to one spatial dimension in ODT permits affordable high resolution of interfacial and single-phase property gradients, which is key to capturing the local behavior of the breakup process and allows simulations at high Reynolds and Weber numbers that are currently not accessible to direct numerical simulations (DNS).

This paper summarizes our extensions of the ODT model to simulate geometrically simple jet breakup problems, including representations of Rayleigh wave breakup, turbulent breakup, and shear-driven breakup. Each jet breakup simulation consists of a short temporal channel section to initialize a turbulent velocity profile at the nozzle exit followed by an adjacent jet section. The simulations are carried out for jet exit Reynolds number of 10000, 23000 and 46000 while the Weber number is varied within the range 102 { 107. We present results on breakup statistics including spatial locations of drop release, drop sizes and liquid core length. The results on primary breakup are compared to experimental results and models.
Original languageEnglish
JournalInternational Journal of Multiphase Flow
Early online date16 Nov 2016
DOIs
Publication statusE-pub ahead of print - 16 Nov 2016

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