Multiscale simulations and experiments on water jet atomization. (October 2017)

• Record Type: Journal Article
• Authors: Saeedipour, Mahdi; Schneiderbauer, Simon; Plohl, Gregor; Brenn, Günter; Pirker, Stefan
• Is Part Of: International journal of multiphase flow. Volume 95(2017)
• Page Start: 71
• Page End: 83
• Publication Date: 2017-10
• Subjects: Jet breakup -- Primary atomization -- Multiscale modelling -- VOF -- LPT -- Phase-Doppler anemometry; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2017.05.006
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: We present a RANS-based multiscale model for simulation of primary atomization. Phase-Doppler anemometry (PDA) experiments were done to characterize water sprays. The model is validated against experimental data using a point-by-point comparison. The model predicts the size and velocity distributions of droplets reasonably. The model requires relatively low computational effort for modeling high-Re sprays. Abstract: Numerical simulation of primary atomization at high Reynolds number is still a challenging problem. In this work a multiscale approach for the numerical simulation of liquid jet primary atomization is applied, using an Eulerian-Lagrangian coupling. In this approach, an Eulerian volume of fluid (VOF) method, where the Reynolds stresses are closed by a Reynolds stress model is applied to model the global spreading of the liquid jet. The formation of the micro-scale droplets, which are usually smaller than the grid spacing in the computational domain, is modelled by an energy-based sub-grid model. Where the disruptive forces (turbulence and surface pressure) of turbulent eddies near the surface of the jet overcome the capillary forces, droplets are released with the local properties of the corresponding eddies. The dynamics of the generated droplets are modelled using Lagrangian particle tracking (LPT). A numerical coupling between the Eulerian and Lagrangian frames is then established via source terms in conservation equations. As a follow-up study to our investigation in Saeedipour et al. (2016a), the present paper aims at modelling drop formation from liquid jets at high Reynolds numbers in the atomization regime and validating the simulation results against in-house experiments. For this purpose, phase-Doppler anemometry (PDA) was used to measure the droplet size and velocity distributions in sprays produced by water jet breakup at different Reynolds numbers in the atomization regime. The spray properties, such as droplet size spectra, local and global Sauter-mean drop sizes and velocity distributions obtained from the simulations are compared with experiment at various locations with very good agreement.