Transitions of deformation to bag breakup and bag to bag-stamen breakup for droplets subjected to a continuous gas flow

Yang, Wei; Jia, Ming; Che, Zhizhao; Sun, Kai; Wang, Tianyou

doi:10.1016/j.ijheatmasstransfer.2017.04.012

Cited by 45 publications

(24 citation statements)

References 52 publications

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“…figure 6). Figures 14 and 15 show a comparison between present analytical and linearised model (with C P = 1) and DNS data of Jain et al (2015), Strotos et al (2016) and Yang et al (2017). The same conclusions as for the comparison with shock tube experiments seems to be valid.…”

Section: Shock Tubesupporting

confidence: 58%

Spheroidal droplet deformation, oscillation and breakup in uniform outer flow

et al. 2020

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Section: Shock Tubesupporting

confidence: 58%

Spheroidal droplet deformation, oscillation and breakup in uniform outer flow

et al. 2020

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“…Rayleigh-Taylor (RT) instability is considered as the main driving mechanism responsible for drop breakup in the general bag breakup or Rayleigh-Taylor piercing (including bag breakup, bag-stamen breakup, dual-bag breakup, bag/plume breakup, multibag breakup, etc.) [65,[71][72][73][74][75][76][77]. All of these breakup modes have the same characteristic bag structure.…”

Section: Secondary Atomizationmentioning

confidence: 99%

Breakup Morphology and Mechanisms of Liquid Atomization

Zhao¹,

Liu²

2020

Environmental Impact of Aviation and Sustainable Solutions

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Fuel atomization, the transformation of bulk liquid into sprays, is of importance in jet engines. In this chapter, we will introduce the latest research advances on breakup morphology and mechanism of liquid atomization. On primary atomization, based on the morphological difference, the twin-fluid atomization could be classified into different regimes. The influence of Kelvin-Helmholtz and Rayleigh-Taylor instability on breakup morphology and fragment size is great and nonmonotonic. On secondary atomization, Rayleigh-Taylor instability is considered as the main driving mechanism in different bag-breakup modes; for higher Weber number, it will be in concurrence with the shear instability. Based on ligamentmediated spray formation model, ligament breakup is found to be well represented by the gamma distributions. Atomization of complex fluids has special characteristics and mechanisms. There are also a lot of research advances recently in this field.

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“…i.e. the flow speed multiplied by time resolution and divided by space resolution, is limited to 0.8 globally and to 0.2 at the interface, and the domain size is ten times larger than the droplet, as suggested by Yang et al (2017).…”

Section: Droplet Distortion Modelmentioning

confidence: 99%

Flow-induced errors in airborne in-situ measurements of aerosols and clouds

Spanu¹,

Dollner²,

Gasteiger³

et al. 2019

Preprint

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Abstract. Aerosols and clouds affect atmospheric radiative processes and climate in many complex ways and still pose the largest uncertainty in current estimates of the Earth’s changing energy budget. Airborne in-situ sensors such as the Cloud, Aerosol, and Precipitation Spectrometer (CAPS) or other optical spectrometers and optical array probes provide detailed information about the horizontal and vertical distribution of aerosol and cloud properties. However, flow distortions occurring at the location where these instruments are mounted on the outside of an aircraft may directly produce artifacts in detected particle number concentration and also cause droplet deformation and/or break-up during the measurement process. Several studies have investigated flow-induced errors assuming that air is incompressible. However, for fast-flying aircraft, the impact of air compressibility is no longer negligible. In this study, we combine airborne data with numerical simulations to investigate the flow around wing-mounted instruments and the induced errors for different realistic flight conditions. A correction scheme for deriving particle number concentrations from in-situ aerosol and cloud probes is proposed, and a new formula is provided for deriving the droplet volume from images taken by optical array probes, reducing errors by up to one order of magnitude. Shape distortions of liquid droplets can either be caused by errors in the speed with which the images are recorded or by aerodynamic forces acting at the droplet surface caused by changes in the airflow around the instrument. These forces can lead to the dynamic breakup of droplets causing artifacts in particle number concentration and size. Furthermore, an estimation of the critical breakup diameter, as a function of flight conditions is provided. Experimental data show that flow speed at the instrument location is smaller than the ambient flow speed. Our simulations confirm the observed difference and reveal a size-dependent impact on particle speed and concentration. This leads, on average, to a 25 % overestimation of the number concentration of particles larger than ~10 μm} diameter and causes distorted images of droplets and ice crystals if the flow values recorded at the instrument are used. With the proposed correction scheme both errors are significantly reduced by a factor 10. Although the presented correction scheme is derived for the DLR Falcon research aircraft (SALTRACE campaign) and validated for the DLR Falcon (A-LIFE campaign) and the NASA DC-8 (ATom campaign), the general conclusions hold for any fast-flying research airplane.

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Transitions of deformation to bag breakup and bag to bag-stamen breakup for droplets subjected to a continuous gas flow

Cited by 45 publications

References 52 publications

Spheroidal droplet deformation, oscillation and breakup in uniform outer flow

Spheroidal droplet deformation, oscillation and breakup in uniform outer flow

Breakup Morphology and Mechanisms of Liquid Atomization

Flow-induced errors in airborne in-situ measurements of aerosols and clouds

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