Characteristics of micro-explosive dispersion of gel fuel particles ignited in a high-temperature air medium

Glushkov, Dmitrii O.; Paushkina, Kristina; Pleshko, A.O.; Vysokomorny, Vladimir S.

doi:10.1016/j.fuel.2021.123024

Cited by 13 publications

(3 citation statements)

References 45 publications

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“…In recent years, gels have been increasingly applied in the food industry (Cao & Mezzenga 2020), medical technology (Narayanaswamy & Torchilin 2019;Daly et al 2020) and fuels and propellants (Glushkov, Pleshko & Yashutina 2020;Padwal, Natan & Mishra 2021;Glushkov et al 2022). The commonly used gels are mostly polymers, whose long-chain molecular structures form strong entangled or cross-linked networks through hydrogen bonds when dispersed in water.…”

Section: Introductionmentioning

confidence: 99%

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Hemline breakup of gel drops subjected to a continuous air flow

et al. 2023

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To explore the effect of yield stress on the secondary breakup of gel drops, experimental and theoretical investigations are carried out by employing a high-speed camera. A unique hemline-type breakup, as a modified behaviour of sheet-thinning breakup, occurs when the air velocity increases to a high region. The edges of the drops constantly deform into thin membranes when the high-velocity air skims over the gel drops. These membranes vibrate vertically, and breaking points occur at high amplitudes, causing the formation of reticular fragments. The results of linear stability analysis indicated that the yield stress of the gel drops has an influence on the formation and breakup of the gel membranes. The breakup regime map and breakup times are also studied.

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Section: Introductionmentioning

confidence: 99%

“…2020) and fuels and propellants (Glushkov, Pleshko & Yashutina 2020; Padwal, Natan & Mishra 2021; Glushkov et al. 2022). The commonly used gels are mostly polymers, whose long-chain molecular structures form strong entangled or cross-linked networks through hydrogen bonds when dispersed in water.…”

Section: Introductionmentioning

confidence: 99%

Hemline breakup of gel drops subjected to a continuous air flow

et al. 2023

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“…A survey of the relevant literature reveals that the combustion behavior of gel fuel has been analyzed either as a function of the initial droplet size and the ambient conditions [ 16 , 17 ] or the functional properties such as the parent fuel, the type of gellant (organic, inorganic, and cryogel) and their concentration [ 15 , 16 , 17 , 21 , 22 , 23 , 24 , 25 , 26 ]. While these studies have focused on determining droplet burn rates, a key mechanism that governs the combustion and jetting behavior in gel fuel droplets is the formation of a gellant shell, whose evolution during the droplet lifetime has been unexplored.…”

Section: Introductionmentioning

confidence: 99%

Time-Varying Oscillatory Response of Burning Gel Fuel Droplets

Sharma

Miglani

2023

Gels

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Gel fuel droplets exhibit disruptive burning due to the rupture of their gellant shell, which causes the release of unreacted fuel vapors from the droplet interior to the flame in the form of jets. In addition to pure vaporization, this jetting allows convective transport for fuel vapors, which accelerates gas-phase mixing and is known to improve droplet burn rates. Using high-magnification and high-speed imaging, this study found that the viscoelastic gellant shell at the droplet surface evolves during the droplet’s lifetime, which causes the droplet to burst at different frequencies, thereby triggering a time-varying oscillatory jetting. In particular, the continuous wavelet spectra of the droplet diameter fluctuations show that the droplet bursting exhibits a nonmonotonic (hump-shaped) trend, where the bursting frequency first increases and then decreases to a point where the droplet stops oscillating. The changes in the shell structure are captured by tracking the temporal variation of the area of rupture sites, spatial movement of their centroid, and the degree of overlap between the rupture areas of successive cycles. During the initial period (immediately following its formation) when the shell is newly formed, it is weak and flexible, which causes it to burst at increasingly high frequencies. This is because the area at and around the rupture site becomes progressively weaker with each rupture in an already weak shell. This is shown by a high degree of overlap between the areas of successive ruptures. On the other hand, the shell flexibility during the initial period is demonstrated by a reversal in the motion of rupture site centroids. However, at later stages when the droplet has undergone multiple ruptures, the depletion of the fuel vapor causes accumulation of gellant on the shell, thus causing the shell to become strong and rigid. This thick, strong, and rigid shell suppresses droplet oscillations. Overall, this study provides a mechanistic understanding of how the gellant shell evolves during the combustion of a gel fuel droplet and causes the droplet to burst at different frequencies. This understanding can be used to devise gel fuel compositions that result in gellant shells with tailored properties, and therefore, control the jetting frequencies to tune droplet burn rates.

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