Investigation on Effect of Gravity Level on Bubble Distribution and Liquid Turbulence Modification for Horizontal Channel Bubbly Flow

Pang, Mingjun; Wei, Jinjia; Yu, Bo

doi:10.1007/s12217-017-9549-6

Cited by 6 publications

(3 citation statements)

References 37 publications

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“…In the space engineering, spacecraft operates in different gravity environments, and the gravity level has significant influence on bubble dynamics, two-phase flow, and heat transfer (Pang et al 2017;Zhang et al 2018). Thus, the effect of gravitational acceleration on quasi-static bubble formation is investigated in this section.…”

Section: Influence Of Gravitational Accelerationmentioning

confidence: 99%

Numerical Simulation of Quasi-Static Bubble Formation from a Submerged Orifice by the Axisymmetric VOSET Method

Wang

Zhao

et al. 2019

Microgravity Sci. Technol.

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In order to investigate the dynamics of quasi-static bubble formation from a submerged orifice, this paper developed an axisymmetric VOSET method with continuum surface force (CSF) model which can accurately capture the moving phase interface of gas-liquid flow. Test case shows that numerical results are in good agreement with experimental results from the literature. The effects of gas flow rate, orifice size, surface tension, contact angle, liquid density, and gravitational acceleration on bubble shape, departure time and departure volume are investigated and analyzed. It is found that increase in orifice size, surface tension, and contact angle results in the increase in the capillary force resisting bubble detachment, which leads to larger departure time and departure volume. But there is a critical contact angle, and contact angle has no significance effect on the process of bubble formation and detachment, when it is smaller than the critical value. Buoyancy force promoting bubble detachment increases with the increase of liquid density and gravitational acceleration, which results in smaller departure time and departure volume. Also, the forming process of the neck shape of bubble bottom at the bubble detachment stage is observed, and the results show that the position of the smallest part of the neck approximately equals to the orifice radius R c .

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Section: Influence Of Gravitational Accelerationmentioning

confidence: 99%

Numerical Simulation of Quasi-Static Bubble Formation from a Submerged Orifice by the Axisymmetric VOSET Method

Wang

Zhao

et al. 2019

Microgravity Sci. Technol.

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“…That is to say, DNS is limited in its applicability to a wide parametric range of bubble states. Non-DNS type computational fluid dynamics (CFD) simulations for BDR have been used in recent years based on the Euler-Euler model Fairweather 2016, Zhao et al, 2019), Euler-Lagrange model (Pang et al, 2014 andRawat et al, 2019), volume-of-fluid model (Hao et al, 2019), level-set approach (Feng et al, 2017), and an improved homogeneous model (Pang et al, 2017). In these models, the physical interaction between bubbles and turbulence is treated with very strong assumptions.…”

Section: Introductionmentioning

confidence: 99%

Wall shear stress modified by bubbles in a horizontal channel flow of silicone oil in the transition region

Oishi

Murai

Tasaka

2020

International Journal of Heat and Fluid Flow

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“…The gravity also has an important influence on the bubbles' dynamics (Xue et al 2016). The bubble distributions (Pang et al 2017) and the bubbles' slip velocity (Chahed et al 2017) can vary under different gravity levels. The effect of bubble break-up and coalescence should be taken into account when the bubble diameter is relatively large (Mohanarangam et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Proper orthogonal decomposition analysis on longitudinal streaks in channel flow laden with micro-bubbles

et al. 2019

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The streaky structures in the fluid laden with and without micro-bubbles of channel turbulent boundary layer flow were experimentally studied by using particle image velocimetry technique at a Reynolds number of Re=9.3×10 4 . Micro-bubbles were produced by the electrolysis of water through platinum wires in a low speed circulating water tunnel. The velocity fields in the streamwise-spanwise plane were obtained at three different heights (i.e. y=3 mm, 5 mm and 7 mm) along the wall-normal direction. The two-point autocorrelation of velocity fluctuations was carried out to identify the scale of the streaky structures in the physical space statistically. The proper orthogonal decomposition (POD) method was employed to analyze the turbulent kinetic energy contents and the streaky structures in mode space. The results show that the streak intensity is decreased and the structures become indistinct in the presence of micro-bubbles at a relatively lower height of the boundary layer in physical space. The ratios of the energy corresponding to leading-order modes to the total energy of the turbulent for the mixed fluid (fluid laden with microbubbles) are smaller than those for the single-phase fluid (fluid without microbubbles) at these three heights. The effect on the energy content is decayed with the increase of POD mode number as well as the normal height in POD mode space for the mixed fluid. Through comparing the streaky and non-streaky turbulent activities in the presence of micro-bubbles, it is found that the streaky | The Japan Society of Fluid Mechanics Fluid Dynamics Research Fluid Dyn. Res. 51 (2019) 035504 (21pp)

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Investigation on Effect of Gravity Level on Bubble Distribution and Liquid Turbulence Modification for Horizontal Channel Bubbly Flow

Cited by 6 publications

References 37 publications

Numerical Simulation of Quasi-Static Bubble Formation from a Submerged Orifice by the Axisymmetric VOSET Method

Numerical Simulation of Quasi-Static Bubble Formation from a Submerged Orifice by the Axisymmetric VOSET Method

Wall shear stress modified by bubbles in a horizontal channel flow of silicone oil in the transition region

Proper orthogonal decomposition analysis on longitudinal streaks in channel flow laden with micro-bubbles

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