Numerical studies of bubble formation dynamics in gas-liquid interaction using Volume of Fluid (VOF) method

Vaishnavi, G.N.V. Sudeepta; Ramarajan, J.; Jayavel, S.

doi:10.1016/j.tsep.2023.101718

Cited by 9 publications

(6 citation statements)

References 24 publications

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“…The existing literature involving multiphase mixing simulation usually focuses on processes in a specific industrial setting, for example, boiling [12][13][14], which is often considered in the context of refrigeration cycles, or bubble dynamics [15][16][17], which is of particular interest in reactor flows [15,18]. However, heat transfer and buoyancy play a dominant role in the flow development of these studies, which is in contrast to the OPSA flow, where a jet through an orifice plate into a confined chamber usually drives the multiphase interaction.…”

Section: Multiphase Mixingmentioning

confidence: 99%

Unsteady Multiphase Simulation of Oleo-Pneumatic Shock Absorber Flow

Sheikh Al-Shabab,

Grenko,

Silva

et al. 2024

Fluids

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The internal flow in oleo-pneumatic shock absorbers is a complex multiphysics problem combining the interaction between highly unsteady turbulent flow and multiphase mixing, among other effects. The aim is to present a validated simulation methodology that facilitates shock absorber performance prediction by capturing the dominant internal flow physics. This is achieved by simulating a drop test of approximately 1 tonne with an initial contact vertical speed of 2.7 m/s, corresponding to a light jet. The flow field solver is ANSYS Fluent, using an unsteady two-dimensional axisymmetric multiphase setup with a time-varying inlet velocity boundary condition corresponding to the stroke rate of the shock absorber piston. The stroke rate is calculated using a two-equation dynamic system model of the shock absorber under the applied loading. The simulation is validated against experimental measurements of the total force on the shock absorber during the stroke, in addition to standard physical checks. The flow field analysis focuses on multiphase mixing and its influence on the turbulent free shear layer and recirculating flow. A mixing index approach is suggested to facilitate systematically quantifying the mixing process and identifying the distinct stages of the interaction. It is found that gas–oil interaction has a significant impact on the flow development in the shock absorber’s upper chamber, where strong mixing leads to a periodic stream of small gas bubbles being fed into the jet’s shear layer from larger bubbles in recirculation zones, most notably in the corner between the orifice plate and outer shock absorber wall.

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Section: Multiphase Mixingmentioning

confidence: 99%

Unsteady Multiphase Simulation of Oleo-Pneumatic Shock Absorber Flow

Sheikh Al-Shabab,

Grenko,

Silva

et al. 2024

Fluids

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“…In this study, we refer to the existing numerical simulations of liquid-gas ejectors as well as multiphase flow algorithms for the computational setup, and the VOF model is selected as the multiphase flow model for the numerical calculations [28][29][30]. The VOF multiphase flow model simulates the multiphase flow equations of motion by using the same set of momentum equations solved jointly for mutually immiscible fluids and calculating the volume fraction of each fluid in motion.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The CFD technique was used to simulate and analyze the swirl number of outlet mixed fluid, the inlet volume, and the specific flow conditions in the flow channel for each model. The swirl elimination study and air intake study performed in this paper on the intelligent toilet cleaning spray bar can not only be used for the development and application of the new intelligent toilet, but also has the same reference value and application for the similar flow channel structure of the fire hose gun [22][23][24], ejector station intake runners, and other scenarios [25][26][27][28][29][30][31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Flow Channel Optimization to Improve the Performance of a Liquid–Gas Ejector for an Intelligent Toilet Spray Bar

Zhou,

Zhu,

Yang

et al. 2023

Atmosphere

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Intelligent toilets can effectively remove odors and harmful substances from exhaust gases and wastewater, maintaining a fresh and clean indoor atmosphere, which is beneficial to the indoor environment and human health. Currently, research on intelligent toilets conducted by sanitary ware manufacturers is still in its early stages. Many of the intelligent toilets available on the market exhibit issues such as an excessive oscillation amplitude of the cleaning spray bar, premature breakdown of the water column, and inadequate air intake. The present study involves the analysis and redesign of a cleaning spray bar model for intelligent toilets. Additionally, several optimization schemes concerning the flow channel of the cleaning spray bar are proposed in order to enhance the performance of the liquid–air ejector. The computational fluid dynamics (CFD) technique is utilized to analyze the water flow characteristics within the cleaning spray bar of the intelligent toilet and to compare and evaluate the proposed schemes. The calculation results indicate that, for the same inlet flow rate, the optimal structure the block with a length of L = 1.5 mm and the block positioned (4). The swirl numbers of these two optimized models are 14.8% and 8.3% of the protype, respectively, while their air intake is 133% and 131% of the protype, respectively. The optimized solutions exhibited significant performance improvements when compared to the prototype. The computational results offer valuable insights for optimizing the flow characteristics of the enhanced product.

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“…This allows the variables and their properties in a given cell to either represent the mixing of phases or simply represent a single phase, depending on the volume fraction of the phases. Based on the volume of fluid method [27], the interface between the gas and liquid phases is determined via solving the continuous equation of the multiphase volume fraction, which is expressed as follows:…”

Section: Flow Modelmentioning

confidence: 99%

Numerical Simulation of Energy and Mass Transfer in a Magnetic Stirring Photocatalytic Reactor

2023

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Hydrogen production via photocatalytic water splitting is one of the promising solutions to energy and environmental issues. Understanding the relationship between hydrogen production in suspended photocatalytic reactions and various influencing factors is crucial for expanding the scale of the system. However, the complexity of physical and chemical factors involved in hydrogen production via photocatalytic water splitting makes systematic research of this technology challenging. In recent research, the simulated light source reactor has become a preferred study object due to its strong controllability. This paper presents a comprehensive energy and mass transfer model for the suspended photocatalytic reaction in a magnetically stirred reactor. The mutual impacts between the flow field, radiation field, and reaction field are analyzed. The simulation results show that the rotating speed of the stirring magneton in the reactor has a significant influence on the flow field. The rotation of the stirring magneton generates a vortex in the central axis area of the reactor, with the relationship between the depth of the vortex f(s) and the rotating speed of the magneton s described as f(s) = 0.27e0.0032s. The distribution of radiation within the reactor is influenced by both the incident radiation intensity and the concentration of the catalyst. The relationship between the penetration depth of radiation g(i) and the incident radiation intensity i is described as g(i) = 10.73ln(i) − 49.59. The relationship between the penetration depth of radiation h(c) and the particle concentration c is given as h(c) = −16.38ln(c) + 15.01. The radiation distribution in the reactor has a substantial impact on hydrogen production, which affects the concentration distribution law of hydrogen. The total amounts of hydrogen generated in the reactor are 1.04 × 10−3 mol and 1.35 × 10−3 mol when the reaction times are 1.0 s and 2.0 s, respectively. This study serves as a foundation for the future scaling of the system and offers theoretical guidance for the optimization of the photocatalytic reactor design and operating conditions.

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Numerical studies of bubble formation dynamics in gas-liquid interaction using Volume of Fluid (VOF) method

Cited by 9 publications

References 24 publications

Unsteady Multiphase Simulation of Oleo-Pneumatic Shock Absorber Flow

Unsteady Multiphase Simulation of Oleo-Pneumatic Shock Absorber Flow

Flow Channel Optimization to Improve the Performance of a Liquid–Gas Ejector for an Intelligent Toilet Spray Bar

Numerical Simulation of Energy and Mass Transfer in a Magnetic Stirring Photocatalytic Reactor

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