6533b853fe1ef96bd12ad611

RESEARCH PRODUCT

Oscillation dynamics of free vortex surface in uncovered unbaffled stirred vessels

Franco GrisafiAntonio BusciglioFrancesca ScargialiAlberto Brucato

subject

EngineeringSlosh dynamicsSettore ING-IND/25 - Impianti ChimiciGeneral Chemical Engineering02 engineering and technologyTurbineIndustrial and Manufacturing EngineeringImpellerMixing020401 chemical engineeringControl theoryUnbaffled stirred tanksEnvironmental ChemistryChemical Engineering (all)0204 chemical engineeringSloshingOscillationbusiness.industryChemistry (all)PropellerGeneral ChemistryMechanicsMacro-instabilitie021001 nanoscience & nanotechnologyVortexRushton turbineFree surfaceSurface-instabilitie0210 nano-technologybusinessUnbaffled stirred tank

description

Abstract The main feature of unbaffled stirred tanks is the highly swirling liquid motion, which leads to the formation of a central vortex on the liquid free surface, when the vessel is operated without top-cover (Uncovered Unbaffled Stirred Tanks, UUST). One of the main drawbacks of such vessels, that limits their industrial applicability, is the possible onset of low-frequency sloshing of the free surface. In this work, original data on oscillation dynamics in UUST are presented. In particular, data focus on the oscillation amplitude as well as on their frequency. Data were obtained by means of a novel experimental technique based on digital image analysis. The effect of impeller geometry (Rushton turbine, pitched blade turbine, Lightnin A310 propeller) and that of scale-up were finally investigated. It was found that the natural oscillation frequencies only depend on vessel scale and geometry, while impeller type plays a role in the way the free surface oscillation frequencies change with impeller speed.

yearjournalcountryeditionlanguage
2016-02-01Chemical Engineering Journal
https://doi.org/10.1016/j.cej.2015.10.015