Experimental and numerical investigation of the primary breakup of an airblasted liquid sheet

Warncke, Katharina; Gepperth, Sebastian; Sauer, Benjamin; Sadiki, A.; Janicka, J.; Koch, Rainer; Bauer, H.-J.

doi:10.1016/j.ijmultiphaseflow.2016.12.010

Cited by 81 publications

(95 citation statements)

References 27 publications

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“…The basis of the diagnostics is an efficient and reliable shadowgraphy setup, which has been successfully used in numerous other studies of the primary breakup of a prefilming airblast atomiser [8,29,34]. The optical schematic is given in Figure 3.…”

Section: Diagnosticsmentioning

confidence: 99%

“…In order to address this issue, a Depth of Field (DoF) calibration is performed, which is discussed in detail by Warncke et al [34]. Briefly, a calibration plate is installed in the test section at the same optical setting like for the actual spray measurements.…”

Section: Post-processing and Calibrationmentioning

confidence: 99%

“…Hence, images of liquid droplets and opaque circles are very similar with the exception of a bright spot (glare point) at the centre of a droplet [38]. This calibration technique was proven to be feasible at several occasions [29,34]. In this study, the DoF correction is enabled since the calibration plate can be moved in the direction perpendicular to the image plane with an accuracy of 1 µm by means of a traverse system.…”

Section: Post-processing and Calibrationmentioning

confidence: 99%

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Microscopic Imaging Spray Diagnostics under High Temperature Conditions: Application to Urea–Water Sprays

2019

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The quantitative investigation of droplet laden turbulent flows at high temperature conditions is of great importance for numerous applications. In this study, an experiment was set up for investigation of evaporating urea-water sprays, which are relevant for the effective reduction of nitrogen oxide emissions of diesel engines using Selective Catalytic Reduction. A shadowgraphy setup is pushed to its limits in order to detect droplet diameters as small as 4 µm and droplet velocities up to 250 m s −1 . In addition, the operating conditions of the gaseous flow of up to 873 K and 0.6 MPa are an additional challenge. Due to the high temperature environment, image quality is prone to be compromised by Schlieren effects and astigmatism phenomena. A water-cooled window and an astigmatism correction device are installed in order to correct these problems. The results to be presented include characteristics of the turbulent gas flow as well as detailed spray characteristics at different positions downstream of the atomiser. It is demonstrated that the velocity of the gas can be approximated by the velocity of the smallest detectable droplets with sufficient accuracy. Furthermore, the statistical analysis of velocity fluctuations provides data for predicting the turbulent dispersion of the droplets.

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Section: Diagnosticsmentioning

confidence: 99%

Section: Post-processing and Calibrationmentioning

confidence: 99%

Section: Post-processing and Calibrationmentioning

confidence: 99%

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Microscopic Imaging Spray Diagnostics under High Temperature Conditions: Application to Urea–Water Sprays

2019

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“…The regularities of the droplet combustion of such fuels have been studied for a long time [7,8] and intensively [9]. However, interest in the combustion of liquid droplets is not reduced to the present time [10,11] due to the complex mechanisms of processes of heat and mass transfer and physicochemical transformations occurring in the drop, on its surface and in the near-surface (or adjacent) layer of the vapor-gas mixture. In particular, up to the present time, the temperature field of droplets is often assumed to be uniform when analyzing the conditions and characteristics of the combustion processes of condensed substances [12].…”

Section: Introductionmentioning

confidence: 99%

Ignition of liquid droplets fuels under conditions of radiation-conductive heating in air

2018

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Abstract.The results of an experimental investigation of ignition liquid fuel (kerosene, diesel fuel) by the single drops under conditions of radiation-conducting heating in air are presented. The dependences of the ignition delay time of the typical fuels droplets on the initial temperature of the heated oxidant in a limited space are established. The parameters of stable ignition of liquid fuel droplets are set.

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“…Nevertheless, spray formation mechanisms due to the disintegration of a liquid film are still not completely known. This type of injector is often studied in a planar geometry [1] [2] [3] because this is the simplest way to analyze the mechanisms of film dynamics and atomization experimentally. At the same time, studies on industrial configurations [4] have shown that the internal geometry of the injector influences strongly the process of atomization.…”

Section: Introductionmentioning

confidence: 99%

Coupled study of film and spray on a basic annular prefiming airblast atomizer

Gosselin

Ferret

Bazile

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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One way to increase efficiency and reduce pollution in transport and energetic domain is designing fuel injectors with better atomization. In this work, experiments were performed on a prefilming airblast atomizer often used in gas turbine engines. For this purpose, a new injector was designed to visualize the prefilming zone and the primary atomization together. The flow configuration corresponds to an annular liquid film sheared by inner high velocity airflows. High speed Shadowgraphy was used to observe film and spray, liquid film frequency, wave velocity and wave deformation, primary breakup regime. Finally, a link between liquid film and the primary atomization are shown first qualitatively and after quantitatively. KeywordsAtomization, liquid film, annular geometry, airblast, prefilming IntroductionOne way to increase efficiency and reduce pollution in transport and energetic domains is designing fuel injectors with better atomization properties [1]. Prefilming airblast atomizers often used in gas turbine engines, offer advantages in terms of atomization quality over a wide range of fuel flow rates. Nevertheless, spray formation mechanisms due to the disintegration of a liquid film are still not completely known. This type of injector is often studied in a planar geometry separately. In this context, we propose an experimental study on the liquid film and the spray for a basic annular prefilming airblast. The paper starts by presenting the experimental set-up designed at IMFT (Institut de Mécanique des Fluides de Toulouse). The destabilization and the atomization of the liquid film have been studied with high speed shadowgraphy method. Then the liquid film is characterized with its different regimes, frequencies of waves, wave velocities and wave deformations. Furthermore observations are made on the regimes of sprays, the possible dependence between the liquid regime and breakup modes. And to finish the preservation between conditions of film near the injector exit and the initial conditions about the primary atomization.

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Experimental and numerical investigation of the primary breakup of an airblasted liquid sheet

Cited by 81 publications

References 27 publications

Microscopic Imaging Spray Diagnostics under High Temperature Conditions: Application to Urea–Water Sprays

Microscopic Imaging Spray Diagnostics under High Temperature Conditions: Application to Urea–Water Sprays

Ignition of liquid droplets fuels under conditions of radiation-conductive heating in air

Coupled study of film and spray on a basic annular prefiming airblast atomizer

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