Energy efficiency of a deep hollow bladed impeller for mixing viscoplastic fluids in a cylindrical vessel

The energy efficiency of a deep hollow blade disk turbine in unbaffled mixing vessel is determined in this article via numerical simulations. The vessel is filled with xanthan gum solutions, which have a shear thinning behavior with yield stress (viscoplastic). The Herschel-Bulkley law is used to model the fluid behavior. Three-dimensional calculations are achieved by the computer tool CFX (version 16.0), and the computational domain is meshed using the software ICEM CFD (version 16.0). Mixing is achieved at low impeller rotational speeds which correspond to the laminar and transitional flow regimes. Our main purpose is to explore the effect of blade size (width and height), Reynolds number, and fluid properties on the mixing efficiency of deep hollow bladed impellers. A validation test of our predicted results with experimental data of a previous study was done, and it has shown a good agreement.

[1]  Zhengming Gao,et al.  Analysis of Turbulence Structure in the Stirred Tank with a Deep Hollow Blade Disc Turbine by Time-resolved PIV , 2010 .

[2]  Consuelo Pizarro,et al.  Scale up and design of processes in aerated-stirred fermenters for the industrial production of vinegar , 2009 .

[3]  Philip K. Chan,et al.  Using computational fluid dynamics modeling to study the mixing of pseudoplastic fluids with a Scaba 6SRGT impeller , 2008 .

[4]  Alvin W. Nienow,et al.  Cavern Sizes Generated in Highly Shear Thinning Viscous Fluids by SCABA 3SHP1 Impellers , 1997 .

[5]  F. Ein-Mozaffari,et al.  Using dynamic tests to study the continuous mixing of xanthan gum solutions , 2008 .

[6]  Leila Pakzad,et al.  Characterisation of the mixing of non‐newtonian fluids with a scaba 6SRGT impeller through ert and CFD , 2013 .

[7]  K. Luyben,et al.  Scale-up of stirring as foam disruption (SAFD) to industrial scale , 2003, Journal of Industrial Microbiology and Biotechnology.

[8]  Philippe A. Tanguy,et al.  Finite element modeling of the laminar and transition flow of the Superblend dual shaft coaxial mixer on parallel computers , 2009 .

[9]  H. Ameur.  Mixing of complex fluids with flat and pitched bladed impellers: Effect of blade attack angle and shear-thinning behaviour , 2016 .

[10]  H. Ameur,et al.  Numerical investigation of flow induced by a disc turbine in unbaffled stirred tank - doi: 10.4025/actascitechnol.v35i3.15554 , 2013 .

[11]  H. Ameur.  Mixing of Shear Thinning Fluids in Cylindrical Tanks: Effect of the Impeller Blade Design and Operating Conditions , 2016 .

[12]  H. Ameur,et al.  Numerical investigation of flow induced by a disc turbine in unbaffled stirred tank , 2015 .

[13]  Leila Pakzad,et al.  Effect of the rheological properties on the mixing of Herschel‐Bulkley fluids with coaxial mixers: Applications of tomography, CFD, and response surface methodology , 2016 .

[14]  Houari Ameur,et al.  Energy efficiency of different impellers in stirred tank reactors , 2015 .

[16]  Shuqing Zhang,et al.  Application Study and Performance Testing of Cross-spring Flexible Hooke Hinge in Static Balancing Instrument , 2015 .

[17]  Leila Pakzad,et al.  Investigation of hydrodynamic performances of coaxial mixers in agitation of yield-pseudoplasitc fluids: Single and double central impellers in combination with the anchor , 2016 .

[18]  B. Junker,et al.  Retrofit of CD-6 (smith) impeller in fermentation vessels , 2000, Applied biochemistry and biotechnology.

[19]  Alvin W. Nienow,et al.  Comparing a range of impellers for "stirring as foam disruption" , 2002 .

[20]  A. Ghenaim,et al.  Numerical study of the performance of multistage Scaba 6SRGT impellers for the agitation of yield stress fluids in cylindrical tanks , 2015 .

[21]  A. Nienow,et al.  Mixing of Highly Viscous Simulated Xanthan Fermentation Broths with the Lightnin A‐315 Impeller , 1992 .

[22]  S. Nagata.  Mixing: Principles and Applications , 1975 .

[23]  Yonggang Zhu,et al.  Impeller Geometry Effect on Velocity and Solids Suspension , 2001 .

[24]  Alvin W. Nienow,et al.  Performance of the scaba 6SRGT agitator in mixing of simulated xanthan gum broths , 1993 .

[25]  Philippe A. Tanguy,et al.  Hydrodynamics characterization of the Maxblend impeller , 2007 .

[26]  M. Mehrvar,et al.  Improving the dynamic performance of continuous-flow mixing of pseudoplastic fluids possessing yield stress using Maxblend impeller , 2012 .