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Bubble Breakup

The Experts below are selected from a list of 879 Experts worldwide ranked by ideXlab platform

Shripad T Revankar – 1st expert on this subject based on the ideXlab platform

  • investigation of Bubble Breakup and coalescence in a packed bed reactor part 1 a comparative study of Bubble Breakup and coalescence models
    International Journal of Multiphase Flow, 2011
    Co-Authors: Daeseong Jo, Shripad T Revankar

    Abstract:

    Abstract In a packed-bed reactor a comparative study of Bubble Breakup and coalescence models has been investigated to study Bubble size distributions as a function of the axial location. The Bubble size distributions are obtained by solving population balance equations that describe gas–liquid interactions. Each combination of Bubble Breakup and coalescence models is examined under two inlet flow conditions: (1) predominant Bubble Breakup flow and (2) predominant Bubble coalescence flow. The resulting Bubble size distributions, Breakup and coalescence rates estimated by individual models, are qualitatively compared to each other. The change of Bubble size distributions along the axial direction is also described with medians. The medians resulting from CFD analyses are compared against the experimental data. Since the predictions estimated by CFD analyses with the existing Bubble Breakup and coalescence models do not agree with the experimental data, a new Bubble Breakup and coalescence model that takes account of the geometry effects is required to describe gas–liquid interactions in a packed-bed reactor.

  • Investigation of Bubble Breakup and coalescence in a packed-bed reactor – Part 1: A comparative study of Bubble Breakup and coalescence models
    International Journal of Multiphase Flow, 2011
    Co-Authors: Daeseong Jo, Shripad T Revankar

    Abstract:

    Abstract In a packed-bed reactor a comparative study of Bubble Breakup and coalescence models has been investigated to study Bubble size distributions as a function of the axial location. The Bubble size distributions are obtained by solving population balance equations that describe gas–liquid interactions. Each combination of Bubble Breakup and coalescence models is examined under two inlet flow conditions: (1) predominant Bubble Breakup flow and (2) predominant Bubble coalescence flow. The resulting Bubble size distributions, Breakup and coalescence rates estimated by individual models, are qualitatively compared to each other. The change of Bubble size distributions along the axial direction is also described with medians. The medians resulting from CFD analyses are compared against the experimental data. Since the predictions estimated by CFD analyses with the existing Bubble Breakup and coalescence models do not agree with the experimental data, a new Bubble Breakup and coalescence model that takes account of the geometry effects is required to describe gas–liquid interactions in a packed-bed reactor.

  • investigation of Bubble Breakup and coalescence in a packed bed reactor part 2 development of a new Bubble Breakup and coalescence model
    International Journal of Multiphase Flow, 2011
    Co-Authors: Daeseong Jo, Shripad T Revankar

    Abstract:

    Abstract A mechanistic model of Bubble Breakup and coalescence has been developed for a packed bed. Bubble Breakup and coalescence models are developed for two coalescence and three Breakup mechanisms by taking account of geometry effects and local flow conditions. The Bubble size distribution estimated with the present Bubble Breakup and coalescence models are compared with the experimental data. Change of Bubble size distributions along the axial direction is studied with the median Bubble size. Median Bubble size as a function of the axial location is estimated under two inlet flow conditions: (1) Bubble Breakup dominated flow and (2) Bubble coalescence dominated flow. The predictions of the median Bubble size with the present model result in the best among other existing Bubble Breakup and coalescence models. However, the prediction of the median Bubble size for the Bubble coalescence dominated flow is still significantly larger than the experimental data. Breakup and coalescence coefficients need to be adjusted in order to predict more accurate Bubble size distributions and median Bubble size for both flow conditions. For the Bubble Breakup dominated flow, the Breakup and coalescence coefficients are found to be 0.35 and 0.4, respectively. For the Bubble coalescence dominated flow, the Breakup and coalescence coefficients are found to be 0.35 and 0.01, respectively.

Tiefeng Wang – 2nd expert on this subject based on the ideXlab platform

  • an improved Bubble Breakup model in turbulent flow
    Chemical Engineering Journal, 2019
    Co-Authors: Huahai Zhang, Guangyao Yang, Ali Sayyar, Tiefeng Wang

    Abstract:

    Abstract An improved Bubble Breakup model has been developed by adequately describing the internal flow inside the deformed Bubble, to account for the significant effect of pressure on the Bubble Breakup behaviors and hydrodynamics in a Bubble column. In this new model, several significant conditions and experimental findings, such as static stress analysis, interfacial stress of Bubble neck, viscous flow resistance, were taken into account. These issues were not considered and led to under-predictions of the Bubble Breakup rate in our previous model. The Bubble Breakup rate and daughter Bubble size distribution predicted by this improved model were consistent with available experimental data. Moreover, this Bubble Breakup model was directly used in the CFD-PBM model to numerically simulate a Bubble column operated at different pressures. A good agreement between the simulated and experimental results was obtained under complex operating conditions.

  • CFD-PBM simulations of a Bubble column with different liquid properties
    Chemical Engineering Journal, 2017
    Co-Authors: Tiefeng Wang, Jinfu Wang

    Abstract:

    Abstract The CFD-PBM coupled model was validated in a Bubble column with organic liquids under industrial conditions. Experimental data of the gas holdup, Bubble size distribution and mass transfer rate were collected from the literature. The liquid viscosity and surface tension were two important parameters affecting the hydrodynamics. Low liquid viscosity and surface tension enhanced the Bubble Breakup but hindered the Bubble coalescence. Compared with water, organic liquids led to a higher gas holdup, smaller Bubble size and larger mass transfer rate. The elevated temperature decreased the liquid viscosity and surface tension. The effects of temperature on the hydrodynamic and gas-liquid mass transfer behaviors were well predicted using the corresponding liquid properties. The CFD-PBM coupled model gave good predictions because it quantitatively described the effect of liquid properties on the Bubble size, interphase forces, turbulence parameters, and Bubble Breakup and coalescence behaviors. The simulations with different Bubble Breakup models showed that the accuracy of the Bubble Breakup model was crucial for reliable predictions of the CFD-PBM coupled model.

  • A unified theoretical model for Breakup of Bubbles and droplets in turbulent flows
    Aiche Journal, 2014
    Co-Authors: Chutian Xing, Tiefeng Wang, Jinfu Wang

    Abstract:

    Pressure has a significant effect on Bubble Breakup, and Bubbles and droplets have very different Breakup behaviors. This work aimed to propose a unified Breakup model for both Bubbles and droplets including the effect of pressure. A mechanism analysis was made on the internal flow through the Bubble/droplet neck in the Breakup process, and a mathematical model was obtained based on the Young–Laplace and Bernoulli equations. The internal flow behavior strongly depended on the pressure or gas density, and based on this mechanism, a unified Breakup model was proposed for both Bubbles and droplets. For the first time, this unified Breakup model gave good predictions of both the effect of pressure or gas density on the Bubble Breakup rate and the different daughter size distributions of Bubbles and droplets. The effect of the mother Bubble/droplet diameter, turbulent energy dissipation rate and surface tension on the Breakup rate, and daughter Bubble/droplet size distribution was discussed. This Bubble Breakup model can be further used in a population balance model (PBM) to study the effect of pressure on the Bubble size distribution and in a computational fluid dynamics-population balance model (CFD-PBM) coupled model to study the hydrodynamic behaviors of a Bubble column at elevated pressures. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1391–1403, 2015

Taotao Fu – 3rd expert on this subject based on the ideXlab platform

  • dynamics and interfacial evolution for Bubble Breakup in shear thinning non newtonian fluid in microfluidic t junction
    Chemical Engineering Science, 2019
    Co-Authors: Hao Zhou, Taotao Fu, Huai Z Li

    Abstract:

    Abstract The dynamics and interfacial evolution for Bubble Breakup in shear-thinning non-Newtonian fluids in microfluidic T-junction were investigated. The Bubble Breakup process includes three stages: squeezing, transition and rapid pinch-off stages. The minimum widths of the Bubble neck in three stages exhibit a power-law relationship with the time or remaining time. Compared to Bubble Breakup in Newtonian fluid, the squeezing stage shortens in non-Newtonian fluid, and the power-law exponent of the rapid pinch-off stage increases with the decrease of the flow index of the CMC solutions. The length of the Bubble tip is linearly stretched with time, and the elongation rate increases with the concentration of CMC solution. The results show that the rheological property of the CMC solution could significantly affect the Bubble Breakup process in the microfluidic T-junction.

  • critical condition for Bubble Breakup in a microfluidic flow focusing junction
    Chemical Engineering Science, 2017
    Co-Authors: Xiaoda Wang, Taotao Fu

    Abstract:

    Abstract The critical condition for Bubble Breakup in a microfluidic flow-focusing junction was studied in this work. The experiments were conducted in a square microchannel of 400 μm wide. The critical condition for Bubble Breakup was investigated by varying the Bubble length l 0 , liquid viscosity μ , velocity of the liquid from the main channel of the flow-focusing junction u 1, and velocity of the liquid from the side channels of the junction u 2 . By analyzing the effects of these factors on the dynamical evolution of gas-liquid interface for Bubble deformation and Breakup, expressions for describing the Bubble deformation and Breakup time were established, respectively. On the basis of these two expressions, the critical condition for the Bubble Breakup in a microfluidic flow-focusing junction was deduced: l 0 w c = 1.5 u 1 u 2 0.75 Ca 2 – 0.13 , where w c is the width of microchannel, Ca 2  =  u 2 μ / γ , and γ is the surface tension.

  • dynamics of Bubble Breakup at a t junction
    Physical Review E, 2016
    Co-Authors: Yutao Lu, Taotao Fu, Huai Z Li

    Abstract:

    The gas-liquid interfacial dynamics of Bubble Breakup in a T junction was investigated. Four regimes were observed for a Bubble passing through the T junction. It was identified by the stop flow that a critical width of the Bubble neck existed: if the minimum width of the Bubble neck was less than the critical value, the Breakup was irreversible and fast; while if the minimum width of the Bubble neck was larger than the critical value, the Breakup was reversible and slow. The fast Breakup was driven by the surface tension and liquid inertia and is independent of the operating conditions. The minimum width of the Bubble neck could be scaled with the remaining time as a power law with an exponent of 0.22 in the beginning and of 0.5 approaching the final fast pinch-off. The slow Breakup was driven by the continuous phase and the gas-liquid interface was in the equilibrium stage. Before the appearance of the tunnel, the width of the depression region could be scaled with the time as a power law with an exponent of 0.75; while after that, the width of the depression was a logarithmic function with the time.