Impact of tank geometry on the maximum turbulence energy dissipation rate for impellers

Zhou, Genwen; Kresta, Suzanne M.

doi:10.1002/aic.690420908

Cited by 181 publications

(144 citation statements)

References 6 publications

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“…After processing the stereo-PIV velocity fields using a global standard deviation filter, and applying the LES analogy of Sheng et al (2000) to the 3-D data, and Kresta (1996). In fact Sheng et al (2000) found that both LES and dimensional analysis yielded similar results.…”

Section: Ratios Of Maximum and Mean Energy Dissipationmentioning

confidence: 99%

“…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%

“…The maximum dissipation rate may deviate significantly from the mean, which may determine, for instance, the minimum drop size in dispersed gas or liquid flows (Zhou and Kresta, 1996), and the rate of fines generation in nano-particle dispersions (Xie et al, 2008). After processing the stereo-PIV velocity fields using a global standard deviation filter, and applying the LES analogy of Sheng et al (2000) to the 3-D data, and Kresta (1996).…”

Section: Ratios Of Maximum and Mean Energy Dissipationmentioning

confidence: 99%

“…All RDT studies listed in Table 1 were carried out using (Chapple et al, 2002) Zhou and Kresta (1996) and TKE balance of Escudie and Line (2003) …”

Section: Ratios Of Maximum and Mean Energy Dissipationmentioning

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: Ratios Of Maximum and Mean Energy Dissipationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Ratios Of Maximum and Mean Energy Dissipationmentioning

confidence: 99%

“…All RDT studies listed in Table 1 were carried out using (Chapple et al, 2002) Zhou and Kresta (1996) and TKE balance of Escudie and Line (2003) …”

Section: Ratios Of Maximum and Mean Energy Dissipationmentioning

confidence: 99%

See 2 more Smart Citations

PIV study of the flow field generated by a sawtooth impeller

Unadkat

Rielly

Nagy

2011

Chemical Engineering Science

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“…• Kinetic energy balance term averaged over a control volume [21][22][23] • Integration of dissipation spectrum [24,25] • Dimensional analysis [26] In the present work, of surface aeration systems has been calculated by using commercial software Visimix [18]. The Visimix [18] program can be helpful in analyzing the mixing parameters in a stirred tanks [27,28].…”

Section: Dissipation Rate Of Turbulent Kinetic Energy εmentioning

confidence: 99%

Energy Dissipation and Shear Rate with Geometry of Baffled Surface Aerator

Kumar

2010

Chem. Eng. Res. Bull.

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Abstract:The geometric parameters of surface aeration systems govern the process phenomena. The dissipation rate of turbulent kinetic energy (ε) and shear rate (γ) are the key process parameters for mixing in surface aerators. Present work by doing numerical computation by visimix analyzes the effect of geometric parameters (impeller diameter, cross-sectional area of the tank, liquid height, width of the baffle, rotor blade length and immersion height) on ε and γ . Analysis has been done by making the geometric parameters non-dimensionalized through rotor diameter. With an increase in liquid height and baffled width, there is an increase in the case of energy dissipation and shear rate values. In the case of tank area and blade length, it is vice versa. Energy dissipation and shear rate are not affected by the variation in immersion height of the impeller.

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Cell damage of microcarrier cultures as a function of local energy dissipation created by a rapid extensional flow

Gregoriades

Clay

et al. 2000

Biotechnol. Bioeng.

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Impact of tank geometry on the maximum turbulence energy dissipation rate for impellers

Cited by 181 publications

References 6 publications

PIV study of the flow field generated by a sawtooth impeller

PIV study of the flow field generated by a sawtooth impeller

Energy Dissipation and Shear Rate with Geometry of Baffled Surface Aerator

Cell damage of microcarrier cultures as a function of local energy dissipation created by a rapid extensional flow

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