Computational study of bubble coalescence/break-up behaviors and bubble size distribution in a 3-D pressurized bubbling gas-solid fluidized bed of Geldart A particles

2021 ◽  
Author(s):  
Teng Wang ◽  
Zihong Xia ◽  
Caixia Chen
Keyword(s):  
Size Distribution ◽  
Fluidized Bed ◽  
Bubble Size ◽  
Computational Study ◽  
Bubble Size Distribution ◽  
Bubble Coalescence ◽  
Break Up

scholarly journals Numerical investigation on the performance of coalescence and break-up kernels in subcooled boiling flows in vertical channels

2016 ◽  
Vol 9 (2) ◽  
pp. 71-85 ◽  
Author(s):  
Sara Vahaji ◽  
Sherman CP Cheung ◽  
Lilunnahar Deju ◽  
Guan Yeoh ◽  
Jiyuan Tu
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Bubble Dynamics ◽  
Interfacial Area ◽  
Bubble Size Distribution ◽  
Heated Wall ◽  
Bubble Coalescence ◽  
Two Phase ◽  
Interfacial Area Concentration ◽  
Break Up

In order to accurately predict the thermal hydraulic of two-phase gas–liquid flows with heat and mass transfer, special numerical considerations are required to capture the underlying physics: characteristics of the heat transfer and bubble dynamics taking place near the heated wall and the evolution of the bubble size distribution caused by the coalescence, break-up, and condensation processes in the bulk subcooled liquid. The evolution of the bubble size distribution is largely driven by the bubble coalescence and break-up mechanisms. In this paper, a numerical assessment on the performance of six different bubble coalescence and break-up kernels is carried out to investigate the bubble size distribution and its impact on local hydrodynamics. The resultant bubble size distributions are compared to achieve a better insight of the prediction mechanisms. Also, the void fraction, bubble Sauter mean diameter, and interfacial area concentration profiles are compared against the experimental data to ensure the validity of the models applied.

Numerical simulation and experimental verification of bubble size distribution in an air dense medium fluidized bed

2013 ◽  
Vol 23 (3) ◽  
pp. 387-393 ◽  
Author(s):  
Jingfeng He ◽  
Yuemin Zhao ◽  
Zhenfu Luo ◽  
Yaqun He ◽  
Chenlong Duan
Keyword(s):  
Numerical Simulation ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Experimental Verification ◽  
Bubble Size ◽  
Bubble Size Distribution ◽  
Dense Medium

Numerical Simulation With a CFD-PBM Model of Hydrodynamics and Bubble Size Distribution of a Rectangle Bubble Column

2016 ◽  
Author(s):  
Yi-Gang Ding ◽  
Xia Lu ◽  
Fu-Li Deng
Keyword(s):  
Size Distribution ◽  
Gas Phase ◽  
Bubble Size ◽  
Discrete Model ◽  
Bubble Column ◽  
Bubble Size Distribution ◽  
Bubble Coalescence ◽  
Complex Behavior ◽  
Gas Velocity ◽  
Superficial Gas Velocity

A coupled CFD-PBM (population balance mode) model is adopted to investigate complex behavior in a rectangle bubble column. In this work The Euler–Euler (E–E) model was adopted for the liquid phase and gas phase, while accounting for bubble coalescence and breakup a PBM discrete model was employed. The total gas holdup for a range of superficial gas velocities were studied and compared with the literature and modest agreement was found. The simulation result shows that the superficial gas velocity has great effect on bubble size distribution, and a wider bubble size distribution is found at higher superficial gas velocity. This indicates an increasing of the superficial gas velocity increases the bubble coalescence and break-up rate.

scholarly journals Investigation on hydrodynamics of gas fluidized bed with bubble size distribution using Energy Minimization Multi Scale (EMMS) mixture model

2018 ◽  
Vol 12 (1) ◽  
pp. 3451-3460 ◽  
Author(s):  
A. Ullah ◽  
◽  
I. Jamil ◽  
S. S. J. Gillani ◽  
A. Hamid ◽  
...  
Keyword(s):  
Size Distribution ◽  
Fluidized Bed ◽  
Mixture Model ◽  
Bubble Size ◽  
Energy Minimization ◽  
Bubble Size Distribution ◽  
Multi Scale

Closure Laws for the Transport Equation of Interfacial Area in Dispersed Flow

2002 ◽  
Author(s):  
X. Rioua ◽  
J. Fabrea ◽  
C. Colin
Keyword(s):  
Transport Equation ◽  
Size Distribution ◽  
Bubble Size ◽  
Interfacial Area ◽  
Bubble Size Distribution ◽  
Bubble Coalescence ◽  
Size Distributions ◽  
Mean Diameter ◽  
The Mean ◽  
Two Fluid

Derivation of a transport equation for the interfacial area concentration. In two-phase flows, the interfacial area is a key parameter since it mainly controls the momentum heat and mass transfers between the phases. An equation of transport of interfacial area may be very useful, especially for the two-fluid models. Such an equation should be able to predict the transition between the flow regimes. With this aim in view, we shall focus our attention on pipe flow. Besides in a first step, our study will be limited to dispersed flows. Different models are used to predict the evolution of bubble sizes. Some models use a population balance that provides a detailed description of the bubble size distributions, but they require as many equations as diameter ranges (Coulaloglou & Tavlarides1). Some others use only one equation for the transport of the mean interfacial area (Hibiki & Ishii2). In that case the bubble size distribution is treated as it would be monodispersed, its mean diameter being equal to the Sauter diameter. An intermediate approach was proposed by Kamp et al.3, in which polydispersed size distributions can be taken into account. It is the starting point of the present study in which: • The choice of an interfacial velocity is discussed. • The sink and source terms due to bubble coalescence, break-up or phase change are established. The model of Kamp et al. consists of transport equations of the various moments of the density probability function P(d) of the bubble diameter. In many experimental situations, P(d) is well predicted by a log-normal law (with two characteristic parameters d00 the central diameter of the distribution and a width parameter): The different moments of order ? of P(d) may be calculated: Sγ=n∫P(d)dγd(d)(1) where n is the bubble number density, S1/n, the mean diameter and S2/?, the interfacial area. A transport equation can be written for each moment: ∂Sγ∂t+∇·(uGSγ)=φγ(2) The lhs of (2) is an advection term by the gas velocity uG and the rhs is a source or sink term due to bubble coalescence, break-up or mass transfer. Since the bubble size distribution is characterised by the two parameters d00 and σˆ, only two transport equations (for S1 and S2) have to be solved to calculate the space-time evolution of the bubble size distribution. These two equations are still too cumbersome for a two-fluid model. Under some hypotheses (σˆ ∼ constant), they are lead to a single equation for the interfacial area. In its dimensionless form the interfacial area ai+ (ai+ = π S2 D, where D is the pipe diameter) reads: d/dt+(ai+)=f(RG,Re,We,ai+)(3) where RG is the gas fraction, Re is the Reynolds number of the mixture, We the Weber number of the mixture and t+ a dimensionless time.

Numerical Simulation of Heterogeneous Bubbly Flow in a Bubble Column

2006 ◽  
Author(s):  
Munenori Maekawa ◽  
Naoki Shimada ◽  
Kouji Kinoshita ◽  
Akira Sou ◽  
Akio Tomiyama
Keyword(s):  
Size Distribution ◽  
Bubble Size ◽  
Bubble Column ◽  
Fluid Model ◽  
Bubbly Flow ◽  
Bubble Size Distribution ◽  
Bubbly Flows ◽  
Bubble Coalescence ◽  
Size Distributions ◽  
Bubble Sizes

Numerical methods for predicting heterogeneous bubbly flows are indispensable for the design of a Fisher-Tropsh reactor for GTL (Gas To Liquid). It is necessary to take into account bubble size distribution determined by bubble coalescence and breakup for the accurate prediction of heterogeneous bubbly flows. Hence we implemented several bubble coalescence and breakup models into the (N+2) field model, which is a hybrid combination of an interface tracking method and a multi-fluid model. Void and bubble size distributions in an open rectangular bubble column were measured and compared with predicted ones. As a result, the following conclusions were obtained: (1) Void and bubble size distributions were not affected by inlet bubble sizes because the bubble size distribution reaches an equilibrium state at which the birth rate is equal to the death rate, and (2) the combination of Luo’s bubble breakup model and a coalescence model consisting of Prince & Blanch’s model and Wang’s wake entrainment model gave good predictions.

Monte Carlo simulation of the bubble size distribution in a fluidized bed with intrusive probes

2012 ◽  
Vol 44 ◽  
pp. 1-14 ◽  
Author(s):  
Martin Rüdisüli ◽  
Tilman J. Schildhauer ◽  
Serge M.A. Biollaz ◽  
J. Ruud van Ommen
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Bubble Size ◽  
Bubble Size Distribution

Effect of Bubble Injection Pattern on the Bubble Size Distribution in a Gas-Solid Fluidized Bed

2017 ◽  
Vol 98 (4) ◽  
pp. 1133-1151 ◽  
Author(s):  
Mohammad H. Tavassoli-Rizi ◽  
Salman Movahedirad ◽  
Ahad Ghaemi
Keyword(s):  
Size Distribution ◽  
Fluidized Bed ◽  
Bubble Size ◽  
Bubble Size Distribution

Bubble size distribution in surface wave breaking entraining process

2007 ◽  
Vol 50 (11) ◽  
pp. 1754-1760 ◽  
Author(s):  
Lei Han ◽  
YeLi Yuan
Keyword(s):  
Surface Wave ◽  
Size Distribution ◽  
Bubble Size ◽  
Wave Breaking ◽  
Bubble Size Distribution
Sign in / Sign up

Export Citation Format

Share Document