The prediction of the cavitation phenomena including population balance modeling

Bannari, Rachid; Hliwa, Ghizlane Zineb; Bannari, Abdelfettah; Belghiti, Mly Taib

doi:10.1063/1.4992159

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…Pinheiro et al [11] evaluated the optimal recirculation rate for an ASBR used in wastewater treatment, demonstrating that the efficiency of the system is limited by mass transfer when operated at low recirculation flow rates. However, higher recirculation rates also promote higher shear stress, [12] and this should be taken into consideration as they can reduce the microbial activity due to the disruption of cells [13] resulting in a process with inefficient fermentation reactions.…”

Section: Introductionmentioning

confidence: 99%

Optimization of bioreactor operating conditions using computational fluid dynamics techniques

Koerich

Rosa

2016

Can J Chem Eng

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High hydraulic retention times are commonly used in bioreactors, as they provide greater contact time between substrate and biomass. These reactors also operate at low flow rates to minimize damage to the biomass due to shear stress and drag. However, a high flow rate provides greater mixing, and thus the optimal operation condition is difficult to estimate. In this study, the effect of different flow rates on the behaviour of the phases in an anaerobic sequencing batch bioreactor is evaluated numerically. Fluent 15 code was used, considering the two‐phase, transient, and turbulent flow in a three‐dimensional mesh. The turbulence, the drag of the biomass flocs to the recirculation system, and the shear stress in the remaining solids were evaluated. For the reactor evaluated in this study, the flow rate of 189.4 g/s was found to be the most suitable, not only for the operation of the reactor, but also to provide energy savings in the operation of the recirculation pump.

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Section: Introductionmentioning

confidence: 99%

Optimization of bioreactor operating conditions using computational fluid dynamics techniques

Koerich

Rosa

2016

Can J Chem Eng

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“…Zwart et al (2004) proposed a new multiphase flow TEM for predicting cavitation based on the Rayleigh-Plesset equation. The simulation accuracy of this cavitation model has been verified in many literatures (Ji et al, 2011(Ji et al, , 2012(Ji et al, , 2013Luo et al, 2012;Ducoin et al, 2012;Huang et al, 2014;Bannari et al, 2017;Taher et al, 2017;Qiu et al, 2018;Cheng et al, 2018). It has been implemented in the commercially available CFD package ANSYS CFX.…”

Section: Introductionmentioning

confidence: 75%

A cavitation model considering thermodynamic and viscosity effects

Pang

Yang

et al. 2018

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Purpose This study aims to develop and validate a new cavitation model that considers thermodynamic effects for high-temperature water flows. Design/methodology/approach The Rayleigh–Plesset equation and “B-factor” method proposed by Franc are used to construct a new cavitation model called “thermodynamic Zwarte–Gerbere–Belamri” (TZGB) by introducing the thermodynamic effects into the original ZGB model. Furthermore, the viscous term of the Rayleigh–Plesset equation is considered in the TZGB model, and the model coefficients are formulated as a function of temperature. Cavitating flows around the NACA0015 hydrofoil under different water temperatures (25°C, 50°C and 70°C) at the angle of attack of 5° are calculated. Findings Results of the investigated temperatures show good agreement with the available experimental data. Given that the thermodynamic and viscosity effects are included in the TZGB model and the model coefficients are treated as a function of temperature, the TZGB model shows better performance in predicting the pressure coefficient distribution and length of cavity than the original ZGB cavitation model and other models do. The TZGB model aims to determine the thermodynamic and viscosity effects and perform better than the other models in predicting the mass transfer rate, particularly in high-temperature water. Originality/value The TZGB model shows potential in predicting the cavitating flows at high temperature and the computational cost of this model is similar to that of the original ZGB model.

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“…In biological applications, high local shear rate was found to influence the growth and morphology of the microorganisms. [32] For example, the microalgal cells were found to be susceptible to aeration associated hydrodynamic stress if the superficial gas velocity 0.01 m/s. [33] Contreras et al [34] showed the importance of bottom and top zones of airlift bioreactor as these two zones were directly related to the high shear rate in the column.…”

Section: Effect Of Gas Flow Rate On Shear Rate and Turbulence Profilesmentioning

confidence: 99%

CFD analysis of flow regimes in airlift reactor using Eulerian‐Lagrangian approach

Pawar

2016

Can J Chem Eng

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The hydrodynamic aspects of the concentric tube airlift reactor have been studied using two‐phase CFD simulations with a Eulerian‐Lagrangian approach. The three‐dimensional CFD simulations are carried out with the experimental geometry of airlift reactor (H/D = 12) reported in the published literature. The standard k‐ϵ turbulence model is used with additional consideration of production and dissipation of buoyancy‐induced turbulence. Two different bubble size distributions (BSDs) and their Sauter mean diameters have been considered to represent the gas distribution at sparger in the reactor. This study shows that the BSD1 (1–5–10 mm) containing a high fraction of small bubbles (≤ 5 mm) represents the hydrodynamics of flows appropriately as compared to the BSD2 (5–10–15 mm) containing a high fraction of large bubbles (≥ 10 mm) or the single size bubble diameters (5.25 mm and 10 mm). Further, three regimes of operation such as no gas bubbles in the downcomer (regime I), stationary gas bubbles in the downcomer (regime II), and gas bubble recirculation from the downcomer section to the riser section (regime III), are verified using CFD simulations with Lagrangian particle tracking. Satisfactory agreement (within 15 % deviation) with the experimental data was observed for parameters such as the gas holdups in the riser and downcomer and the liquid circulation velocity in the flow regimes I and II for BSD1.

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The prediction of the cavitation phenomena including population balance modeling

Cited by 5 publications

References 11 publications

Optimization of bioreactor operating conditions using computational fluid dynamics techniques

Optimization of bioreactor operating conditions using computational fluid dynamics techniques

A cavitation model considering thermodynamic and viscosity effects

CFD analysis of flow regimes in airlift reactor using Eulerian‐Lagrangian approach

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