Effect of Large Amplitude Waves and Film Inertia on Mass Separation at a Sharp Corner

Sadeghizadeh, Zahra; Drallmeier, J. A.

doi:10.1115/1.4039514

Cited by 3 publications

(2 citation statements)

References 24 publications

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“…When LAWs with significant mass content reach the sharp corner, they become detached from the corner and lead to a higher percentage of mass separation. This is consistent with previous study presented by [16].…”

Section: Prediction Of Mass Separation For Flow Regime Without Law (Film Inertia Effect)supporting

confidence: 94%

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Mass Separation Regimes for Shear-Driven Liquid Film at Expanding Corners

Sadeghizadeh

Drallmeier

2021

ICLASS

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Separation of gas-driven liquid film from an expanding corner is encountered in many applications such as port fuel injection (PFI) and air-fuel mixing in jet engines. However, physical insight about the liquid mass separation from expanding corners is very limited. Experimental studies show two different flow regimes in shear-driven flows: flow regime where there is no large amplitude waves at the interface and flow regime with large amplitude waves at the interface. Correspondingly liquid mass separation is shown to occur due to two effects: uniform film inertia and large amplitude waves at the interface. In absence of large amplitude waves for large corner angle, the liquid mass separation could occur purely due to uniform film inertia. Two distinct correlations have been proposed for each flow regime based on operating parameters. The controlling parameters, which affect the liquid mass separation at the corner are gas and liquid Reynolds numbers, liquid film properties, and corner angle. Additionally, the proposed correlations would probably need a larger dataset for a robust consistency evaluation.

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Section: Prediction Of Mass Separation For Flow Regime Without Law (Film Inertia Effect)supporting

confidence: 94%

“…Moreover, liquid film propagation was predicted based on a boundary layer description. Typical predicted results are shown in [16].…”

Section: High Speed Imaging Techniquementioning

confidence: 98%

Mass Separation Regimes for Shear-Driven Liquid Film at Expanding Corners

Sadeghizadeh

Drallmeier

2021

ICLASS

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Effect of liquid viscosity and surface tension on mass separation of shear-driven liquid film at a sharp corner

Sadeghizadeh

Drallmeier

2019

International Journal of Multiphase Flow

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Influence of the ambient pressure on the liquid accumulation and on the primary spray in prefilming airblast atomization

Chaussonnet

Gepperth

Holz

et al. 2020

International Journal of Multiphase Flow

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The influence of the ambient pressure on the breakup process is investigated by means of PIV and shadowgraphy in the configuration of a planar prefilming airblast atomizer. The ambient pressure is varied from 1 to 8 bar. Other investigated parameters are the gas velocity and the film loading. From single-phase PIV measurements, it is found that the gas velocity in the vicinity of the prefilmer partly matches the analytical profile from the near-wake theory. The shadowgraphy images of the liquid phase directly downstream of the prefilmer allow to extract characteristic quantities of the liquid accumulation at the atomizing edge. Two different characteristic lengths, as well as the ligament velocity and a breakup frequency are determined. In addition, the droplets generated directly downstream of the liquid accumulation are captured. Hence, the spray Sauter Mean Diameter (SMD) and the mean droplet velocity are given for each operating point. A scaling law of these quantities with regard to ambient pressure is derived. A correlation is observed between the characteristic length of the accumulation and the SMD, thus promoting the idea that the liquid accumulation determines the primary spray characteristics. An threshold to distinguish the zones between primary and secondary breakup is proposed based on an objective criterion. It is also shown that taking non-spherical droplets into account significantly modifies the shape of the dropsize distribution, thus stressing the need to use shadowgraphy when investigating primary breakup. The ambient pressure and the velocity are varied accordingly to keep the aerodynamic stress ρ g U 2 g constant. This leads to almost identical liquid accumulation and spray characteristics. Hence, it is confirmed that the aerodynamic stress is a more appropriate parameter than the gas velocity or the ambient pressure to characterize prefilming airblast breakup. Finally, SMD correlations from the literature are compared to the present experiment. Most of the correlations calibrated with LDA/LDT measurement underestimate the SMD. This highlights the need to use shadrowgraphy for calibrating primary breakup models.

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Effect of Large Amplitude Waves and Film Inertia on Mass Separation at a Sharp Corner

Cited by 3 publications

References 24 publications

Mass Separation Regimes for Shear-Driven Liquid Film at Expanding Corners

Mass Separation Regimes for Shear-Driven Liquid Film at Expanding Corners

Effect of liquid viscosity and surface tension on mass separation of shear-driven liquid film at a sharp corner

Influence of the ambient pressure on the liquid accumulation and on the primary spray in prefilming airblast atomization

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