Flow instabilities associated with impeller clearance changes in stirred vessels

C Galletti; A Paglianti; K C Lee; M Yianneskis

doi:10.1080/00986440590477953

Flow instabilities associated with impeller clearance changes in stirred vessels

C Galletti, A Paglianti, K C Lee, M Yianneskis

King's College London

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Flow instabilities associated with changes in the clearance (C) of a Rushton impeller from the bottom of a stirred vessel of diameter T=294 mm were studied experimentally with laser Doppler anemometry. It is shown that for C/T=0.17-0.18 flow changes from a double- to a single-loop pattern occur randomly. The transition from one regime to the other is characterized by periodic oscillations at a frequency (f) related to the impeller speed (N) by f/N=0.135. The lifetimes of the stable and unstable patterns were found to be affected by fluid density and viscosity as well as clearance. The implications of the results for both mixing processes in stirred vessels and related predictions of the flows are discussed

Original language	English
Pages (from-to)	516 - 531
Number of pages	16
Journal	CHEMICAL ENGINEERING COMMUNICATIONS
Volume	192
Issue number	4
DOIs	https://doi.org/10.1080/00986440590477953
Publication status	Published - Apr 2005

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title = "Flow instabilities associated with impeller clearance changes in stirred vessels",

abstract = "Flow instabilities associated with changes in the clearance (C) of a Rushton impeller from the bottom of a stirred vessel of diameter T=294 mm were studied experimentally with laser Doppler anemometry. It is shown that for C/T=0.17-0.18 flow changes from a double- to a single-loop pattern occur randomly. The transition from one regime to the other is characterized by periodic oscillations at a frequency (f) related to the impeller speed (N) by f/N=0.135. The lifetimes of the stable and unstable patterns were found to be affected by fluid density and viscosity as well as clearance. The implications of the results for both mixing processes in stirred vessels and related predictions of the flows are discussed",

author = "C Galletti and A Paglianti and Lee, {K C} and M Yianneskis",

year = "2005",

month = apr,

doi = "10.1080/00986440590477953",

language = "English",

volume = "192",

pages = "516 -- 531",

journal = "CHEMICAL ENGINEERING COMMUNICATIONS",

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number = "4",

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T1 - Flow instabilities associated with impeller clearance changes in stirred vessels

AU - Galletti, C

AU - Paglianti, A

AU - Lee, K C

AU - Yianneskis, M

PY - 2005/4

Y1 - 2005/4

N2 - Flow instabilities associated with changes in the clearance (C) of a Rushton impeller from the bottom of a stirred vessel of diameter T=294 mm were studied experimentally with laser Doppler anemometry. It is shown that for C/T=0.17-0.18 flow changes from a double- to a single-loop pattern occur randomly. The transition from one regime to the other is characterized by periodic oscillations at a frequency (f) related to the impeller speed (N) by f/N=0.135. The lifetimes of the stable and unstable patterns were found to be affected by fluid density and viscosity as well as clearance. The implications of the results for both mixing processes in stirred vessels and related predictions of the flows are discussed

AB - Flow instabilities associated with changes in the clearance (C) of a Rushton impeller from the bottom of a stirred vessel of diameter T=294 mm were studied experimentally with laser Doppler anemometry. It is shown that for C/T=0.17-0.18 flow changes from a double- to a single-loop pattern occur randomly. The transition from one regime to the other is characterized by periodic oscillations at a frequency (f) related to the impeller speed (N) by f/N=0.135. The lifetimes of the stable and unstable patterns were found to be affected by fluid density and viscosity as well as clearance. The implications of the results for both mixing processes in stirred vessels and related predictions of the flows are discussed

U2 - 10.1080/00986440590477953

DO - 10.1080/00986440590477953

M3 - Article

VL - 192

SP - 516

EP - 531

JO - CHEMICAL ENGINEERING COMMUNICATIONS

JF - CHEMICAL ENGINEERING COMMUNICATIONS

IS - 4

ER -

Flow instabilities associated with impeller clearance changes in stirred vessels

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