Gas-liquid flows in cylindrical venturi scrubbers: Boundary layer separation in the diffuser section

Azzopardi, B.J.

doi:10.1016/0300-9467(92)85025-5

Cited by 21 publications

(4 citation statements)

References 15 publications

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“…In addition, the divergent angle of the diffuser used in this study is large (usually is around 7°) and is not likely to be encountered in practice, since large diffuser angles would cause excessive pressure losses due to flow recirculation in the regions adjacent to the diffuser walls. This effect is commonly known as stalling (Wade and Fowler, 1974;Azzopardi, 1992). Fathikalajahi et al (1996) proposed a three-dimensional model that takes into account nonuniformity of drop distribution by considering liquid jet penetration developed by Viswanathan et al (1983).…”

Section: Literature Reviewmentioning

confidence: 99%

Modeling of Venturi Scrubber Performance

Viswanathan¹

1997

Ind. Eng. Chem. Res.

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The performance of the Brink and Contant industrial-size Venturi scrubber has been successfully simulated by means of a two-dimensional computer model. The two-phase, two-component, annular flow occurring in the unit was predicted using a Particle-In-Cell (PIC) numerical technique. Consideration of four different dust diameters, ranging from 0.5 to 10 µm, allowed evaluation of the Venturi grade efficiency curve. Liquid jet penetration and drop size distributions, incorporated as important parameters, were linked to significant liquid maldistribution in the Venturi throat. This study confirmed the observation that the drops are actually classified by inertial effects which enable bigger drops to penetrate further into the central core of the air stream and the smaller drops to stay closer to the duct walls. As a result, the smaller drops were not observed in the region occupied by the larger drops. This liquid maldistribution persisted throughout the scrubber and resulted in predictions of particulate collection efficiency that were lower than would be expected with the usual assumption of uniformly distributed drops of one size using one-dimensional models. Because this two-dimensional model can incorporate different liquid injection modes and drop size distributions, it provides considerable versatility for the simulation of cleaning processes in Venturi scrubbers.

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Section: Literature Reviewmentioning

confidence: 99%

Modeling of Venturi Scrubber Performance

Viswanathan¹

1997

Ind. Eng. Chem. Res.

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“…3b can be seen that a part of the injected liquid is attached to thc wall forming a turbulent wavy film and is dragged by the airflow vcrtically upward. In general, the liquid jet atomization in a self-priming venturi scrubber corrcsponds well with the observations performed by other researchers in forced feed venturi scrubbers (i.c., Mayingcr and Neumann, 1978;Roberts and Hill, 1981;Azzopardi, 1992). Regarding the jct breakup, no diffcrcnccs between the two alternative operating modes have been observed.…”

Section: Liquid Disintegration and Jet Penetration In The Venturi Scrmentioning

confidence: 99%

Aerosol Separation Efficiency of a Venturi Scrubber Working in Self-Priming Mode

Lehner

1998

Aerosol Science and Technology

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ABSTRACT. This study deals with the operating behavior, the liquid disiutegration, and the aerosol collection efficiency of a venturi scrubber working in selfpriming mode. In the case of a forced feed venturi scrubber, the scrubbing liquid is injected into the throat by means of a pump. The liquid load is adjustable independently from the gas flow rate. In contrast, the venturi scrubber analyzed in the present investigation works in a self-priming mode. The washing liquid is introduced due to a pressure difference between the inside and the outside of the venturi throat. This pressure difference is composed of the hydrostatic pressure of the liquid and the static pressure of the flowing gas. The atomization process of the injected liquid is equivalent to the observations made with forced feed venturi scrubbers. However, the jet penetration is most sensitive to the operating conditions of the scrubber. The cleaning efficiency of a venturi scrubber as well as the overall pressure loss grow with an increasing liquid load and with an increasing gas velocity in the throat. The separation efficiency and energy consumption of the scrubber have to be optimized. It is shown that the separation efficiency can be improved by a multistage injection of the scrubbing liquid. Due to the self-priming operation mode, the separation efficiency remains on a high level even if the gas velocity decreases. This does not require any regulation from the outside. Finally, a short prospect is given on the industrial application of the described self-priming venturi scrubber. AEROSOL SCIENCE AND TECFINOLOGY 28:389-402 (1998)

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“…Later on, Viswanathan et al [17] developed an annular flow pressure drop model in which a constant core quality throughout the venturi were assumed. After that their model was improved by considering the growth and separation of the gas boundary layer [3,4]. Allen and van Santen [1] considered the importance of dry pressure drop in venturi scrubbers and compared the experimental pressure drop with the predicted values.…”

Section: Introductionmentioning

confidence: 99%