Experimental study on the bubble breakage in a stirred tank. Part 1. Mechanism and effect of operating parameters

Hasan, Basim O.

doi:10.1016/j.ijmultiphaseflow.2017.08.006

Cited by 34 publications

(31 citation statements)

References 40 publications

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“…The increased fouling rate with increasing Re h is ascribed to the increased mass transport of oil from the bulk to the wall on which the oil deposits. This agrees with finding of Wang et al When Re h increases, the turbulence and turbulent pressure fluctuation in the pipe core are increased . This leads to enhance the oil transport form the fluid bulk to the wall by forced convection to deposit on the surface leading to increase the fouling rate.…”

Section: Resultssupporting

confidence: 91%

Oil fouling in double‐pipe heat exchanger under liquid‐liquid dispersion and the influence of copper oxide nanofluid

Majdi

Alabdly

Hasan

et al. 2019

Heat Trans. Asian Res.

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Dispersions of oil in water are encountered in a variety of industrial processes leading to a reduction in the performance of the heat exchangers when thermally treating such two phase fluids. This reduction is mainly due to changes in the thermal and hydrodynamical behavior of the two phase fluid. In the present work, an experimental investigation was performed to study the effects of light oil fouling on the heat transfer coefficient in a double-pipe heat exchanger under turbulent flow conditions. The effects of different operating conditions on the fouling rate were investigated including: hot fluid Reynolds number (the dispersion), cold fluid Reynolds number, and time. The oil fouling rate was analyzed by determining the growth of fouling resistance with time and through pressure drop measurements. The influence of copper oxide (CuO) nanofluid on the fouling rate in the dispersion was also determined. It was found that the presence of dispersed oil causes a reduction in heat transfer coefficient by percentages depending on the Reynolds number of both cold and hot fluids and the concentration of oil. In addition, the time history of fouling resistance exhibited different trends with the flow rates of both fluids and its trend was influenced appreciably by the presence of CuO nanofluid. K E Y W O R D S copper oxide, dispersion, double-pipe heat exchanger, fouling, heat transfer, nanofluid, oil Heat Transfer-Asian Res.

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Section: Resultssupporting

confidence: 91%

Oil fouling in double‐pipe heat exchanger under liquid‐liquid dispersion and the influence of copper oxide nanofluid

Majdi

Alabdly

Hasan

et al. 2019

Heat Trans. Asian Res.

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“…The velocity magnitude is high and can be further increased as the dimensionless frequency can be raised to four times the range we measured; the proposed degassing unit would be thrice as large. We achieved Re = 10 6 which (8) p = ∫ R 0 2 rdr should be sufficient in theory because experiments in water [13] show that a turbulent flow of Re = 4 × 10 4 is necessary to break bubbles of size 2..4 mm. For bubble collapse, the absolute velocity value is not important; rather, the root mean squared (RMS) velocity or turbulence generation rate is important.…”

Section: Resultsmentioning

confidence: 86%

“…The physical properties of GaInSn (see Table 1) corresponds to a fully turbulent flow with Re = 5 × 10 5 . Analysis of mechanically stirred water [13] has shown that a Reynolds number of at least 2 × 10 4 is necessary for 2 to 4 mm bubble breakup to occur. Higher rotational frequencies were not measured owing to limitations of the UDV system.…”

Section: Resultsmentioning

confidence: 99%

Contactless Aluminum Degassing System—GaInSn Model Experiments and Numerical Study

Baranovskis

Berenis

Grants

et al. 2021

J. Sustain. Metall.

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Hydrogen dissolves in molten aluminum and it is essential to reduce hydrogen concentration before making aluminum product. We propose a novel contactless degassing method that uses electromagnetic forces to drive the melt flow and split the injected inert gas bubbles. A numerical and experimental model of the proposed system were studied with a focus on characterizing permanent magnet-driven flows. For solving the multiphysics problem numerically, we coupled OpenFoam for hydrodynamic calculations and Elmer for electromagnetic calculations. The velocity field and developed pressure in a laboratory-scale physical model built using GaInSn in different operating regimes were examined and compared with the numerical model predictions. To characterize the conditions for bubble collapse, velocity pulsations were measured, and turbulence generation rate was computed. The results verify the feasibility of scaling the proposed degassing system. By implementing this gas purging method, the need of a rotating impeller and its associated problems would be eliminated.

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“… The length-to-diameter L/D ratio: varied over constant vessel volume to analyse different temperature distribution behaviours within the model, as illustrated in Table II. The ratio was varied according to experimental work on stirred tanks in literature [19][20][21].  Wall thickness t mm: taken as spacing between the reactor's wall and the jacket used.…”

Section: Materials and Methods A) Generalised Carbonation Reactormentioning

confidence: 99%

Optimisation of Carbonation Reactor Design Using Multiphysics Models for Precipitated Calcium Carbonate PCC Production

Elzaki¹

2020

IRJIET

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Temperature distributions in the carbonation reactor with an inner diameter of 4.23m and overall length of 7m is numerically modelled. This is motivated by the need to lower overall capital and operating costs, and to optimise the carbonation process performance, simultaneously. In this paper, computational simulations are used to design an industrial scale carbonation reactor 89.72m 3 consisting of an external cooling jacket. Several parameters are varied including reactor's geometry (6 shapes), wall thickness (100, 200, and 300mm), cooling jacket temperature (15, 25, and 35ºC), and material type. These parameters are varied interchangeably to compare temperature probe plots at a point probe (1.5,0) located closer to the cooling jacket region. Simulations in COMSOL ® Multiphysics 5.2a show that partial Carbon Steel AISI 4340 jackets with a 100mm distance, between vessel wall and outside wall of jacket, while operating at ambient temperature range of 20-25ºc, can achieve the required operating temperature i.e. 50±5ºC. Then, the precipitation process of the calcium carbonate (PCC) is maximised. This result in decreased bare materials' capital costs by 95.87% and 97.39% compared to Nickel and Titanium, respectively. The need for cooling the water for the jacket is eliminated, while operating costs are lowered by 25-50% per 10ºC. A simplified experimental setup is proposed to demonstrate the coupling of COMSOL ® simulations with experimental work can be a reliable and an effective method to evaluate the carbonation reactor model design.

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Experimental study on the bubble breakage in a stirred tank. Part 1. Mechanism and effect of operating parameters

Cited by 34 publications

References 40 publications

Oil fouling in double‐pipe heat exchanger under liquid‐liquid dispersion and the influence of copper oxide nanofluid

Oil fouling in double‐pipe heat exchanger under liquid‐liquid dispersion and the influence of copper oxide nanofluid

Contactless Aluminum Degassing System—GaInSn Model Experiments and Numerical Study

Optimisation of Carbonation Reactor Design Using Multiphysics Models for Precipitated Calcium Carbonate PCC Production

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