Energy dissipation and macro instabilities in a stirred square tank investigated using an LE PIV approach and LDA measurements

Kilander, Jesper; Rasmuson, Anders

doi:10.1016/j.ces.2005.02.076

Cited by 38 publications

(24 citation statements)

References 19 publications

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“…The large eddy approach depends on the large velocity gradients in the vicinity of the impeller, which rapidly decrease in the main flow direction, whereas dimensional analysis produced a more even distribution of  along the discharge stream. The comparison between the LES result and dimensional analysis is in agreement with the findings of Kilander and Rasmuson (2005), who obtained a five-times greater mean dissipation rate from the LES analogy, and also noted a significant difference in distribution between the two methods.…”

Section: Dissipation Ratesupporting

confidence: 80%

“…The calculation of  has been the subject of many previous works (e.g. Kresta and Wood, 1993;Wu and Patterson, 1989;Zhou and Kresta, 1996;Baldi and Yianneskis, 2003;Ducci and Yianneskis, 2005;Sharp and Adrian, 2001;Khan, 2005, Kilander andRasmuson, 2005;Sheng et al, 2000); a comparison between the different methods has not been provided in this paper (but may be found in the work of Unadkat (2010)). It is now well known that the LES analogy provides the best approximation (Khan, 2005;Gabriele et al, 2009), and hence this method has been employed here to estimate the dissipation rate.…”

Section: Introductionmentioning

confidence: 99%

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PIV study of the flow field generated by a sawtooth impeller

Unadkat

Rielly

Nagy

2011

Chemical Engineering Science

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Stereoscopic and high-speed particle image velocimetry (PIV) techniques have been employed to study the flow field induced by a sawtooth (EkatoMizer) impeller, operated in the fully turbulent flow regime at an impeller speed of 1500 rpm.Ensemble-averaged mean flow fields and turbulence quantities were calculated for a region close to the impeller blades. The flow was found to be anisotropic near the impeller and exhibited return-to-isotropy behaviour further away from it. Macroinstabilities were found to have a high probability of occurrence in the discharge stream. All three velocity components from the stereo-PIV measurements were used to estimate the dissipation rate, by adopting a large eddy simulation (LES) analogy.Spurious vectors distorting the dissipation rate calculation were identified, and various standard deviation filters were applied for vector validation. By evaluating the filtered dissipation rate profiles against the multi-fractal intermittency model of Meneveau and Sreenivasan (1991), the global standard deviation filter was found to be the most suitable type. The ratio of the maximum to the mean dissipation rate for the EkatoMizer discharge stream was found to be similar to that reported for Rushton disk turbine and pitched-blade turbine impellers in the literature, raising questions about the reported high-shear advantage of sawtooth impellers.

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Section: Dissipation Ratesupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

PIV study of the flow field generated by a sawtooth impeller

Unadkat

Rielly

Nagy

2011

Chemical Engineering Science

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“…The stirrer speed, the tip speed, the Reynolds number and the average velocity gradient for the different configurations are shown in Table 2. The power consumption per volume used in the higher energy input was the same as the one used in the dissipation study by Kilander and Rasmuson (2005).…”

Section: Set-upmentioning

confidence: 99%

Scale-up behaviour in stirred square flocculation tanks

Kilander

Blomström

Rasmuson

2007

Chemical Engineering Science

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“…This similar approach called Large eddy PIV was used for dissipation of turbulent kinetic energy in an agitated vessel e.g. by [5,14,8,10,11]. The basic presumption should be fulfilled: grid size has to be in inertial sub-range, where turbulent kinetic energy is transferred from large scales to small ones.…”

Section: Large Eddy Piv Approachmentioning

confidence: 99%

“…[4][5][6][7][8][9][10][11][12], but the results of absolute values of local dissipation rates have not been accomplished yet. While formerly a temporal record of instantaneous velocities [3,12] or two point measurement [9] was used for determination of dissipation rate, nowadays determination from velocity field obtained by PIV method [5,6,8,10,11] is preferred. This trend will be probably continued according to measurement techniques development to fully 3D measurements with resolution up to Kolmogorov scales.…”

Section: Introductionmentioning

confidence: 99%

Estimation of turbulence dissipation rate by Large eddy PIV method in an agitated vessel

Kysela

Jašíková

Konfršt

et al. 2015

EPJ Web of Conferences

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Abstract. The distribution of turbulent kinetic energy dissipation rate is important for design of mixing apparatuses in chemical industry. Generally used experimental methods of velocity measurements for measurement in complex geometries of an agitated vessel disallow measurement in resolution of small scales close to turbulence dissipation ones. Therefore, Particle image velocity (PIV) measurement method improved by large eddy PIV approach was used. Large eddy PIV method is based on modeling of smallest eddies by a sub grid scale (SGS) model. This method is similar to numerical calculations using Large Eddy Simulation (LES) and the same SGS models are used. In this work the basic Smagorinsky model was employed and compared with power law approximation. Time resolved PIV data were processed by Large Eddy PIV approach and the obtained results of turbulent kinetic dissipation rate were compared in selected points for several operating conditions (impeller speed, operating liquid viscosity).

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Energy dissipation and macro instabilities in a stirred square tank investigated using an LE PIV approach and LDA measurements

Cited by 38 publications

References 19 publications

PIV study of the flow field generated by a sawtooth impeller

PIV study of the flow field generated by a sawtooth impeller

Scale-up behaviour in stirred square flocculation tanks

Estimation of turbulence dissipation rate by Large eddy PIV method in an agitated vessel

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