Numerical prediction of air-assisted primary atomization using Smoothed Particle Hydrodynamics

Braun, Samuel; Wieth, Lars; Holz, Simon; Dauch, Thilo F.; Keller, Marc C.; Chaussonnet, Geoffroy; Gepperth, Sebastian; Koch, Rainer; Bauer, Hans‐Jörg

doi:10.1016/j.ijmultiphaseflow.2019.03.008

Cited by 35 publications

(19 citation statements)

References 30 publications

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“…Pre-Processing based on CAD-Model SPH-Simulation of Primary Breakup A CAD file defining the geometry of a nozzle can be used as input for the generation of wall particle distributions supported by the CAD2SPH workflow presented by Dauch et al [12]. In a next step, the simulation is performed by means of a highly efficient SPH solver as presented according to (please refer to Braun et al [13] for details about the validation). Finally, the resulting SPH data sets are investigated qualitatively and quantitatively by means of the interactive data exploration environment "postAtom", which was jointly developed and implemented at the Institut für Visualisierung und Datenanalyse as presented by Dauch et al [11].…”

Section: Data Exploration Using "Postatom"mentioning

confidence: 99%

Analyzing the Interaction of Vortex and Gas–Liquid Interface Dynamics in Fuel Spray Nozzles by Means of Lagrangian-Coherent Structures (2D)

et al. 2019

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Predictions of the primary breakup of fuel in realistic fuel spray nozzles for aero-enginecombustors by means of the SPH method are presented. Based on simulations in 2D, novel insightsinto the fundamental effects of primary breakup are established by analyzing the dynamics ofLagrangian-coherent structures (LCSs). An in-house visualization and data exploration platformis used in order to retrieve fields of the finite-time Lyapunov exponent (FTLE) derived from theSPH predictions aiming at the identification of time resolved LCSs. The main focus of this paperis demonstrating the suitability of FTLE fields to capture and visualize the interaction between thegas and the fuel flow leading to liquid disintegration. Aiming for a convenient illustration at a highspatial resolution, the analysis is presented based on 2D datasets. However, the method and theconclusions can analoguosly be transferred to 3D. The FTLE fields of modified nozzle geometriesare compared in order to highlight the influence of the nozzle geometry on primary breakup, whichis a novel and unique approach for this industrial application. Modifications of the geometry areproposed which are capable of suppressing the formation of certain LCSs, leading to less fluctuationof the fuel flow emerging from the spray nozzle.

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Section: Data Exploration Using "Postatom"mentioning

confidence: 99%

Analyzing the Interaction of Vortex and Gas–Liquid Interface Dynamics in Fuel Spray Nozzles by Means of Lagrangian-Coherent Structures (2D)

et al. 2019

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“…The numerical performance of the SPH code developed at the Institut für Thermische Strömungsmaschinen (ITS) has been demonstrated recently [26]. A 3D SPH simulation with this code has proved the capability of the SPH method to predict the primary breakup process accurately compared to experimental data [14,26], in particular the drop size. Using 2D SPH simulations of the primary breakup at ambient pressure, the effect of the trailing edge thickness on the atomization process has been clarified [27].…”

Section: Methodsmentioning

confidence: 98%

“…This method was originally developed for astrophysics [16,17] and later adapted to free surface flow applications [18]. In recent years, the SPH method has been applied to air-assisted liquid atomization [14,19,20].…”

Section: Methodsmentioning

confidence: 99%

“…With this formalism the Navier-Stokes equations can be cast into an SPH formulation, as explained in [14]. To close the system, the Tait equation of state is used.…”

Section: Methodsmentioning

confidence: 99%

“…Hence, some attempts have been made to predict the atomization process numerically from first principles. In the context of prefilming airblast atomization, Euler-Euler [11][12][13] and Lagrange-Lagrange [14] approaches have been developed to resolve the gas-liquid interface. Two-phase simulations at elevated pressure have been conducted using both fully Eulerian methods [12] as well as fully Lagrangian methods [15].…”

Section: Introductionmentioning

confidence: 99%

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Close Nozzle Spray Characteristics of a Prefilming Airblast Atomizer

et al. 2019

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The formation of pollutant emissions in jet engines is closely related to the fuel distribution inside the combustor. Hence, the characteristics of the spray formed during primary breakup are of major importance for an accurate prediction of the pollutant emissions. Currently, an Euler–Lagrangian approach for droplet transport in combination with combustion and pollutant formation models is used to predict the pollutant emissions. The missing element for predicting these emissions more accurately is well defined starting conditions for the liquid fuel droplets as they emerge from the fuel nozzle. Recently, it was demonstrated that the primary breakup can be predicted from first principles by the Lagrangian, mesh-free, Smoothed Particle Hydrodynamics (SPH) method. In the present work, 2D Direct Numerical Simulations (DNS) of a planar prefilming airblast atomizer using the SPH method are presented, which capture most of the breakup phenomena known from experiments. Strong links between the ligament breakup and the resulting spray in terms of droplet size, trajectory and velocity are demonstrated. The SPH predictions at elevated pressure conditions resemble quite well the effects observed in experiments. Significant interdependencies between droplet diameter, position and velocity are observed. This encourages to employ such multidimensional interdependence relations as a base for the development of primary atomization models.

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