Study of primary instability of thick liquid films under strong gas shear

Isaenkov, Sergey V.; Cherdantsev, Andrey V.; Vozhakov, I. S.; Cherdantsev, Mikhail V.; Архипов, Д. Г.; Маркович, Д. М.

doi:10.1016/j.ijmultiphaseflow.2018.11.010

Cited by 30 publications

(13 citation statements)

References 41 publications

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“…A large number of particles will be extruded and piled up in the pore due to the small pore size of the filter membrane. According to the “three stages of film formation theory, , the particles will deform after extrusion, − and the outlines between the particles are not clear, forming continuous films (Figure d), blocking the pores, and the inks cannot be filtered normally at a low T g (24–38 °C). As the T g increased (38–48 °C), the deformed tendency of particles was not obvious and couldnot form continuous films at the initial filtration (Figure e).…”

Section: Resultsmentioning

confidence: 99%

Ink-Jet Printing of Colored Latex Inks with a “Soft” Core–“Hard” Shell Structure

Yang

Yin

Sheng

et al. 2023

ACS Appl. Polym. Mater.

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Colored latex particles (CLPs) as a novel colorant have been widely applied to salt-free dyeing and printing due to their adjustable composition, brilliant colors, excellent durability, and small particle size. In this paper, the effects of glass-transition temperatures (T g) on the filterability of CLP inks were first studied, and the results showed that the CLP inks can be successfully filtered and ejected when the T g’s of CLP inks exceeded 48 °C. Based on our previous research, CLP (T g = 25 °C)-printed fabrics had excellent color fastness and a soft hand feel, while a stiff hand feel occurred with the increase of the T g. Herein, the CLPs with a core–shell structure (CLP@PS) were designed using CLPs (T g = 25 °C) as a “soft” core for ensuring the color fastness of printed fabrics and PS as a “hard” core for ensuring excellent filterability of inks. Transmission electron microscopy and dynamic light scattering indicated that the prepared particles had an obvious core–shell structure, and the particle size was 96 nm. To balance the filterability of inks and color fastness of printed fabrics, the encapsulated thickness was optimized at 20 nm by adjusting the amounts of styrene (St) and 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AIBA). The flow rate and filtration time of CLP@PS inks were 8.9 mL/s, and 11 s, respectively. Finally, the CLP@PS inks were applied to ink-jet printing of cotton fabric. Compared with pigment ink-jet printing, CLP@PS-printed fabrics had a softer hand feel and better rubbing and washing fastness.

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Section: Resultsmentioning

confidence: 99%

Ink-Jet Printing of Colored Latex Inks with a “Soft” Core–“Hard” Shell Structure

Yang

Yin

Sheng

et al. 2023

ACS Appl. Polym. Mater.

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“…Liquid flow rates for water were selected to correspond to the liquid film Reynolds numbers of 140, 220 and 300, which were employed in [29]. The liquid Reynolds number is defined as: Three working liquids were used: water and two water-glycerol solutions with a mass concentration of glycerol of 20% and 33% (WGS1 and WGS2, respectively).…”

Section: Methodsmentioning

confidence: 99%

“…Liquid flow rates for water were selected to correspond to the liquid film Reynolds numbers of 140, 220 and 300, which were employed in [29]. The liquid Reynolds number is defined as:…”

Section: Methodsmentioning

confidence: 99%

“…The measurements of local instantaneous film thickness were conducted using the shadow technique, used, e.g., in [21,30]. In the present paper, we employed the same configuration as used in [29]. The detailed methodical analysis of the technique can be found in that paper; here, a brief description of its principles is given.…”

Section: Methodsmentioning

confidence: 99%

“…The main idea of our recent paper [29] was that the modeling of waves in annular flow had to consecutively deal with all the stages of the waves' evolution and be conducted in close relation to the experiments. The paper was focused on the investigation of the initial waves and liquid film at this stage of evolution.…”

Section: Of 14mentioning

confidence: 99%

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Effect of Liquid Viscosity and Flow Orientation on Initial Waves in Annular Gas–Liquid Flow

et al. 2020

Self Cite

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The complex wave structure of annular gas–liquid flow with disturbance waves and liquid entrainment is a result of the evolution of high-frequency initial waves, appearing at the very inlet of the flow, prior to the hydrodynamic stabilization of liquid film. This stage of flow evolution is studied experimentally, using a shadow technique, and theoretically, using a linear stability analysis of the Orr–Sommerfeld equation in both phases. The present work is focused on the comparison of earlier results obtained in air–water downward flow with the new results obtained in upward flow and with more viscous liquids. The flow orientation affects the shape of the liquid film prior to stabilization; the initial film area is thicker but shorter in upward flow. Upward flow orientation also leads to a lower frequency and the increment of growth of initial waves. The viscosity effect is found to be weak if flow rates of both phases are the same. The model is mostly able to reproduce the qualitative trends, but the quantitative agreement is not reached. Experimental observations indicate that the liquid flow within the initial area is significantly different from the stabilized flow of gas-sheared liquid film, which is used in the model. This difference could explain the discrepancy; further development of the model should be aimed at taking into account the evolution of the velocity profile inside the liquid film during the stage of hydrodynamic stabilization.

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Prediction model of volume average diameter and analysis of atomization characteristics in electrostatic atomization minimum quantity lubrication

Jia

Liu

et al. 2023

Friction

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Minimum quantity lubrication (MQL) is a relatively efficient and clean alternative to flooding workpiece machining. Electrostatic atomization has the merits of small droplet diameter, high uniformity of droplet size, and strong coating, hence its superiority to pneumatic atomization. However, as the current research hotspot, the influence of jet parameters and electrical parameters on the average diameter of droplets is not clear. First, by observing the shape of the liquid film at the nozzle outlet, the influence law of air pressure and voltage on liquid film thickness (h) and transverse and longitudinal fluctuations are determined. Then, the mathematical model of charged droplet volume average diameter (VAD) is constructed based on three dimensions of the liquid film, namely its thickness, transverse wavelength (λh), and longitudinal wavelength (λz). The model results under different working conditions are obtained by numerical simulation. Comparisons of the model results with the experimental VAD of the droplet confirm the error of the mathematical model to be less than 10%. The droplet diameter distribution span value Rosin-Rammler distribution span (R.S) and percentage concentrations of PM10 (particle size of less than 10 µm)/PM2.5 (particle size of less than 2.5 µm) under different working conditions are further analyzed. The results show that electrostatic atomization not only reduces the diameter distribution span of atomized droplets but also significantly inhibits the formation of PM10 and PM2.5 fine-suspension droplets. When the air pressure is 0.3 MPa, and the voltage is 40 kV, the percentage concentrations of PM10 and PM2.5 can be reduced by 80.72% and 92.05%, respectively, compared with that under the pure pneumatic atomization condition at 0.3 MPa.

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Study of primary instability of thick liquid films under strong gas shear

Cited by 30 publications

References 41 publications

Ink-Jet Printing of Colored Latex Inks with a “Soft” Core–“Hard” Shell Structure

Ink-Jet Printing of Colored Latex Inks with a “Soft” Core–“Hard” Shell Structure

Effect of Liquid Viscosity and Flow Orientation on Initial Waves in Annular Gas–Liquid Flow

Prediction model of volume average diameter and analysis of atomization characteristics in electrostatic atomization minimum quantity lubrication

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