Primary break-up characterisation and droplet statistics of multi-hole sprays using a probabilistic surface density methodology

Tretola, Giovanni ; Navarro-Martinez, Salvador ; Vogiatzaki, Konstantina

Resumen: The work provides novel physical insight into the complex near-field flow dynamics and the primary break-up characteristics of sprays injected through multi-hole injectors (gasoline ECN Spray G). We use a stochastic fields transported-PDF method ( --PDF ) that allows for more accurate modelling of the sub-grid dynamics. Within this framework, the joint sub-grid probability density function of the liquid volume and surface density is solved using stochastic methods. Initially, the predicted spray dynamics resulting from the primary atomisation are simulated in terms of droplet size, velocity and spray angle. The spray from each hole is then investigated individually. The distribution of liquid near the nozzles agrees very well to the available experimental measurements. It is found that the spray break-up process in these gasoline sprays produces a quasi-lognormal droplet distribution. Such normalised distributions can be used to feed Eulerian–Lagrangian approach, showing a great potential to represent the full spray combustion process coupling the two approaches. Moreover, comparing the statistical and radial distributions of the droplets, we observe that the core of the plumes are characterised by larger droplets (≥10 μm), although the overall spray is represented by lower size droplets surrounding the plume centre (≤10 μm). Finally, the paper shows that the geometry asymmetry has a considerable effect on the flow field, which in turn affects the droplet behaviour. Even if the average droplet size was not affected by the asymmetry, the droplet velocity presented significant variation ( ≈ 50% ) for some of the holes.

Idioma: Inglés

DOI: 10.1016/j.ijmultiphaseflow.2022.104039

Año: 2022

Publicado en: INTERNATIONAL JOURNAL OF MULTIPHASE FLOW 152 (2022), 104039 [13 pp.]
ISSN: 0301-9322

Factor impacto JCR: 3.8 (2022)

Categ. JCR: MECHANICS rank: 36 / 137 = 0.263 (2022) - Q2 - T1

Factor impacto CITESCORE: 7.0 - Engineering (Q1) - Chemical Engineering (Q2) - Physics and Astronomy (Q1)

Factor impacto SCIMAGO: 0.985 - Fluid Flow and Transfer Processes (Q1) - Physics and Astronomy (miscellaneous) (Q1) - Mechanical Engineering (Q1)

Tipo y forma: Article (PrePrint)