Nonlinear dynamics of self-organising bubble departures from twin nozzles

Dzienis, Paweł; Mosdorf, Romuald; Wyszkowski, T.

doi:10.1007/s11012-019-01056-6

Cited by 7 publications

(9 citation statements)

References 19 publications

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“…It can, thus, be inferred that it is the existence of the adjacent active site that causes the deviation of bubble trajectories and makes the bubbles move closer to each other. In the experiment of the isothermal bubble generation system by Dzienis et al, 31 the same trajectories were also observed to show that the bubbles departed from the twin sources attracted each other and moved ward into a single chain.…”

Section: Self-organized Bubble Trajectories From Two Nucleation Sitesmentioning

confidence: 62%

Numerical study on the activation of nucleation sites and bubble interactions in twin-bubble nucleate boiling

Pan

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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The present study aims to investigate the interplay between the activation behavior of neighboring nucleation sites and the corresponding bubble dynamics in twin-bubble nucleate boiling. For this purpose, boiling of water on a copper heater with two nucleation sites is simulated by using a thermal-hydrodynamic coupling method. This method treats active nucleation sites as vapor sources, and the vapor generation rates from the nucleation sites are incorporated into the two-phase flow simulation as the inlet boundary conditions at the corresponding sites, which are computed via a dynamic model of microlayer evaporation. Various sizes and arrays of cavities are considered to investigate the activation timing of the nucleation sites, temperature fluctuations of the heated surface, and dynamics of the two bubbles. The simulated results show that the hydrodynamic interaction between the adjacent bubbles can cause the alternative activation of the nucleation sites and lead to irregular fluctuations to the temperature of the heated surface. The difference of the critical activation superheats between the neighboring nucleation sites can induce intermittent activation of the nucleation sites accompanied with a waiting time of the activation for the smaller-size cavity. The smaller the cavity is, the longer the waiting time of the activation becomes. The two bubbles growing from different nucleation sites are observed to approach each other, which stem from the wake flow left by the neighboring rising bubbles.

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Section: Self-organized Bubble Trajectories From Two Nucleation Sitesmentioning

confidence: 62%

Numerical study on the activation of nucleation sites and bubble interactions in twin-bubble nucleate boiling

Pan

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…In this method, subsequent coordinates of attractor points are calculated based on the samples between which the distance is equal to the time delay (τ). The proper value of time delay (τ) was estimated using the following criterion [20]: ( )~0.5 (0) (7) with the autocorrelation function, (Ca) of the form given by [18]:…”

Section: Priodicity Of Bubble Departuresmentioning

confidence: 99%

“…The chaotic nature of bubble departure has been extensively investigated [4,5,6,7,8], and from these investigations it can be concluded that two groups of phenomena are responsible for the occurrence of chaotic bubble departures: the particular dynamics of the bubble flow in the liquid as well as the hydrodynamics of liquid flow around the capillary [4,8,9,10] and the erratic changes of pressure in the gas supply system that accompany this flow [4,5,9,12,13]; these phenomena are connected with the nonlinear dynamics of the capillary filling process. These dynamics are sensitive to the physical and chemical properties of the two-phase system, notably the viscosity and surface tension, and to the container geometry and have been previously investigated [14].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Water Hardness Perturbations on Bubble Departure Dynamics

Dzienis

Mosdorf

Czarnecki

2021

Preprint

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The influence of small changes to water hardness on the nonlinear behaviour of liquid penetration into a capillary and the resulting air pressure fluctuations during air bubble formation are examined in this paper. Experiments were undertaken in which bubbles were generated both in water having a surface tensile force of σ = 72.2 mN/m and in an aqueous solution of calcium carbonate having a surface tensile force of σ = 75.4 mN/m, each contained in a glass capillary with an internal diameter of 1 mm. It is shown that both the maximum value of liquid penetration into the capillary and bubble growth time are affected by perturbations to the water hardness. The time it takes for the bubble to depart the capillary was estimated using the following nonlinear data analysis methods: time delay (τ), attractor reconstructions, correlation dimension (D), and largest Lyapunov exponent (λ). All estimates demonstrate that the pressure fluctuations in the c-c aqueous solutions and extent of liquid solution penetration into the capillary during the time between subsequent bubble departures behave chaotically.

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“…Therefore, it is necessary to understand the processes of bubble formation, bubble flow and its stability. The experimentally and numerically investigations of the bubble formation [1,6], bubble coalescence [7,8], gas bubble trajectories [9,10] or chaotic bubble behaviours [11][12][13] are still conducted.…”

Section: Introductionmentioning

confidence: 99%

JRP analysis of synchronization loss between signals recording during bubble departures

2022

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The synchronization between the air pressure fluctuations and the depth of liquid penetration into the nozzle during bubble departures was investigated using joint recurrence quantification analysis. In the experiment, the bubbles were generated from a glass nozzle into distilled water. During the analysis, the recurrent rate coefficients were calculated for the depth of liquid penetration into the glass nozzle and pressure changes in the gas supply system. The study was conducted by two air volume flow rates, i.e. 0.023 l/min and 0.026 l/min. The air volume flow rates were selected so that the appearance and disappearance of period bubble departures were clearly visible. It has been shown that the synchronization of the pressure changes and the depth of liquid penetration appears when periodic changes in the depth of liquid penetration occur in a relatively long period of time. The process of changing the distance between the extremes of liquid penetration into the nozzle and pressure changes in the gas supply system was observed. It has been found that the decrease in the distance between these extremes is responsible for the appearance of periodic bubble departures. This behaviour has not been reported in previous papers. This process was modelled by numerical simulations.

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Nonlinear dynamics of self-organising bubble departures from twin nozzles

Cited by 7 publications

References 19 publications

Numerical study on the activation of nucleation sites and bubble interactions in twin-bubble nucleate boiling

Numerical study on the activation of nucleation sites and bubble interactions in twin-bubble nucleate boiling

The Influence of Water Hardness Perturbations on Bubble Departure Dynamics

JRP analysis of synchronization loss between signals recording during bubble departures

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