Investigation of air-assisted sprays submitted to high frequency transverse acoustic fields: Droplet clustering

Ficuciello, Antonio; Blaisot, Jean‐Bernard; Richard, Christine; Baillot, Françoise

doi:10.1063/1.4985202

Cited by 20 publications

(16 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This phenomenon is difficult to observe on experimental images for the present operating conditions due to the presence of multiple ligaments and droplets hiding the liquid core. However, it has already been observed by Ficuciello et al (2017) for other operating conditions with lower momentum flux ratio and gaseous Weber number. Back then, the authors explained this deformation by considering the acoustic radiation pressure distribution p rad (θ) around the liquid jet.…”

Section: Flattening Of the Liquid Corementioning

confidence: 74%

“…To investigate interaction mechanisms between acoustics and two-phase flows in injection conditions representative of those in LRE, the experimental configuration of Ficuciello et al (2017), from Coria laboratory, is simulated. The experimental test-rig, represented on figure 3, consists in a cavity equipped with four speakers at the bottom and a coaxial injector at the top.…”

Section: Computational Domain and Meshmentioning

confidence: 99%

“…The operating conditions investigated in the present contribution have been selected in collaboration with Coria in order to meet with both experimental and numerical requirements. As a result, the liquid mass flow rate has been increased compared to operating conditions studied by Ficuciello et al (2017) in order to limit computational costs. Water and air are both injected at atmospheric pressure and a temperature of 300 K. This gives rise to a momentum flux ratio J = 4 and a gaseous Weber number We g = 490, according to the following expressions:…”

Section: Operating and Boundary Conditionsmentioning

confidence: 99%

“…Regarding the spray, another noticeable impact of acoustics have been observed by Baillot et al (2009) and consists in a transverse deviation of droplets due to acoustic radiation forces. Finally, Baillot et al (2009) and Ficuciello et al (2017) observed a change in the shape of the atomized jet, under specific operating conditions, due to a drastic expansion of the spray angle in the direction orthogonal to the acoustic propagation axis. Given all these observations, it appears that the combustion stability may thus be strongly affected by the impact of acoustics on the atomized liquid phase.…”

Section: Introductionmentioning

confidence: 96%

“…To do so, the numerical investigation has to be performed on atomization regimes representative of LRE. The experimental configuration of Ficuciello et al (2017) is then simulated and the numerical specifications of this simulation are presented in section 3. To the authors' knowledge, this represents the first numerical study of the unsteady response of a nonreactive shear coaxial flow to transverse acoustic modulation under subcritical operating conditions.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Large-eddy simulation of an air-assisted liquid jet under a high-frequency transverse acoustic forcing

Rutard

Dorey

Touze

et al. 2020

International Journal of Multiphase Flow

View full text Add to dashboard Cite

The present contribution lies on the high-frequency combustion instability issue occurring in liquid rocket engines, and focuses on subcritical operating conditions. Thanks to the development of high-performance computing and advanced numerical simulation codes, large-eddy simulation has become an essential analysis tool in the domain. Different unsteady numerical strategies exist to handle the wide range of time and length scales involved in two-phase flows related to subcritical operating conditions, but only a few are adapted to deal with reactive flows. What is more, most of them are developed without any consideration for possible acoustic effects on atomization processes while these may have a great impact on the stability of the engine. Therefore, the present contribution aims at evaluating the ability of one of these numerical strategies in particular to render acoustic effects on atomized liquid jets typical of what happens under unstable operating conditions. To do so, the numerical simulation of a non-reactive two-phase flow submitted to a transverse acoustic modulation is performed. Two cases are simulated, the first one with acoustic modulation, the jet lying in the vicinity of a transverse intensity anti-node, and the second one without any. In order to highlight the effect of acoustics on the liquid phase, the two cases are compared to one another as well as to experiments presented in the literature. The numerical strategy used in these simulations is based on the coupling between a diffuse interface method for the simulation of large liquid structures, and a kinetic-based Eulerian model for the description of droplets. It is found that the flattening of the liquid core under acoustic constraints is retrieved in the simulations. This flattening process thus induces a decrease of the liquid core length and an intensification of its stripping. The additional mass of liquid thus ripped from the liquid jet is transformed into droplets and the spray undergoes a drastic modification of its shape thanks to an appropriate primary atomization source term. Finally, periodic oscillations of droplets under the acoustic velocity are rendered thanks to the coupling between the gaseous phase and the spray through a drag source term. The numerical strategy thus appears adapted to deal with numerical simulations of coaxial two-phase flows under transverse acoustic modulation, in which the response of the gas, the liquid core and the spray are all linked to one another. This strategy can then be used for future numerical studies of high-frequency combustion instabilities.

show abstract

Section: Flattening Of the Liquid Corementioning

confidence: 74%

Section: Computational Domain and Meshmentioning

confidence: 99%

Section: Operating and Boundary Conditionsmentioning

confidence: 99%