Investigation of the impact of high liquid viscosity on jet atomization in crossflow via high-fidelity simulations

Abstract

Atomization of extremely high viscosity liquid can be of interest for many applications in aerospace, automotive, pharmaceutical, and food industries. While detailed atomization measurements usually face grand challenges, high-fidelity numerical simulations offer the advantage to comprehensively explore the atomization details. In this work, a previously validated high-fidelity first-principle simulation code HiMIST is utilized to simulate high-viscosity liquid jet atomization in crossflow. The code is used to perform a parametric study of the atomization process in a wide range of Ohnesorge numbers (Oh = 0.004–2) and Weber numbers (We = 10–160). Direct comparisons between the present study and previously published low-viscosity jet in crossflow results are performed. The effects of viscous damping and slowing on jet penetration, liquid surface instabilities, ligament formation/breakup, and subsequent droplet formation are investigated. Complex variations in near-field and far-field jet penetrations with increasing Oh at different We are observed and linked with the underlying jet deformation and breakup physics. Transition in breakup regimes and increase in droplet size with increasing Oh are observed, mostly consistent with the literature reports. The detailed simulations elucidate a distinctive edge-ligament-breakup dominated process with long surviving ligaments for the higher Oh cases, as opposed to a two-stage edge-stripping/column-fracture process for the lower Oh counterparts. The trend of decreasing column deflection with increasing We is reversed as Oh increases. A predominantly unimodal droplet size distribution is predicted at higher Oh, in contrast to the bimodal distribution at lower Oh. It has been found that both Rayleigh-Taylor and Kelvin-Helmholtz linear stability theories cannot be easily applied to interpret the distinct edge breakup process and further study of the underlying physics is needed.

Analysis of viscous fluid flow in a pressure-swirl atomizer using large-eddy simulation

“…Computational tools offer a way to study the process from perspectives that are often inaccessible with experimental or analytical methods. Most computational primary atomization studies have considered round jets (Shinjo and Umemura, 2011;Yang and Turan, 2017), planar liquid sheets (Desjardins and Pitsch, 2010), or jets in cross flow (Herrmann, 2010;Li et al, 2017), while detailed computational studies on annular swirling liquid sheets have been more rare. Such studies include, for example, the paper by Ding et al (2016) on the atomization mechanism of a hollow cone swirling spray in a typical simplex atomizer.…”

Numerical Simulations of Combustion Instabilities in a Combustor with an Augmentor-Like Geometry

“…Inviscid fluxes are computed using a blended central/upwind scheme called limited-linear. Verification of these numerics is provided elsewhere [41][42][43][44]. Finally, note that OpenFOAM solvers or earlier versions have been observed to reproduce satisfactory results in a large variety of combustion problems [19,39,[45][46][47][48][49][50][51].…”

“…Verification of these numerics is provided 90 elsewhere [37-40]. Finally, note that OpenFOAM solvers or earlier versions have been observed to 91reproduce satisfactory results in a large variety of combustion problems[15,35,[41][42][43][44][45][46][47].…”

An Artificial Neural Network for the Prediction of Penetration Height of Aerated Elliptical Liquid Jets in Gaseous Crossflows

“…), the presence of aerating gas within the liquid, and etc. [2], [7]- [10]. In addition, many researchers attribute the stated discrepancies to the measurement techniques incorporated to derive the correlations as well as the challenges in finding the boundaries of the sprays [4].…”