Mechanical mixing efficiency parameter for static mixers

AIChE Journal ◽  
1983 ◽  
Vol 29 (1) ◽  
pp. 159-161 ◽  
Author(s):  
J. M. Ottino
Keyword(s):  
Mixing Efficiency ◽  
Mechanical Mixing ◽  
Static Mixers ◽  
Efficiency Parameter

scholarly journals Optimization of mixing in stirred bioreactors, 2: Selection of optimum impeller combinations for non-aerated simulated broths

2007 ◽  
Vol 13 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Anca-Irina Galaction ◽  
Elena Folescu ◽  
Dan Cascaval
Keyword(s):  
Fermentation Broth ◽  
Mixing Time ◽  
Maximum Level ◽  
Specific Power ◽  
Mixing Efficiency ◽  
Mechanical Mixing ◽  
Rushton Turbine ◽  
Shear Effects ◽  
Stirred Bioreactors ◽  
Selection Of

Although radial impellers, especially the Rushton turbine, are widely used in stirred bioreactors, their applicability is limited by the high apparent viscosities of the broths. For optimizing mechanical mixing by selecting the appropriate impeller for a specific fermentation broth or process, the comparative analysis of the mixing efficiency, energy costs and shear effects on the biocatalysts is required. By means of this analysis, three different combinations of radial impellers for water and viscous simulated broths were selected for attaining optimum mixing in a bioreactor. The proposed impellers combinations offer the most intense and uniformly distributed mixing and the lowest specific power consumption required for reaching a maximum level of mixing time of less than one minute.

scholarly journals Granular flow in static mixers by coupled DEM/CFD approach

2016 ◽  
Vol 70 (5) ◽  
pp. 539-546 ◽  
Author(s):  
Lato Pezo ◽  
Milada Pezo ◽  
Aca Jovanovic ◽  
Nenad Kosanic ◽  
Aleksandar Petrovic ◽  
...  
Keyword(s):  
Granular Flow ◽  
Fluid Dynamic ◽  
Mixing Time ◽  
Numerical Approach ◽  
Mixing Efficiency ◽  
Multiphase Model ◽  
Static Mixer ◽  
Mixing Process ◽  
Static Mixers ◽  
Relative Standard

The mixing process greatly influence the mixing efficiency, as well as the quality and the price of the intermediate and/or the final product. Static mixer is used for premixing action before the main mixing process, for significant reduction of mixing time and energy consumption. This type of premixing action is not investigated in detail in the open literature. In this article, the novel numerical approach called Discrete Element Method is used for modelling of granular flow in multiple static mixer applications (1 - 3 Komax or Ross mixing elements were utilized), while the Computational Fluid Dynamic method was chosen for fluid flow modelling, using the Eulerian multiphase model. The main aim of this article is to predict the behaviour of granules being gravitationally transported in different mixer configuration and to choose the best configuration of the mixer taking into account the total particle path, the number of mixing elements and the quality of the obtained mixture. The results of the numerical simulations in the static mixers were compared to experimental results, the mixing quality is examined by RSD (relative standard deviation) criterion, and the effects on the mixer type and the number of mixing elements on mixing process were studied. The effects of the mixer type and the number of mixing elements on mixing process were studied using analysis of variance (ANOVA). Mathematical modelling is used for optimization of number of Ross and Komax segments in mixer in order to gain desirable mixing results.

scholarly journals One Dimensional Modeling of Jet Diffusion Flame

2018 ◽  
Vol 16 (4) ◽  
Author(s):  
Angan Sengupta ◽  
A.K. Gupta ◽  
I.M. Mishra ◽  
S. Suresh
Keyword(s):  
Diffusion Flame ◽  
Flame Temperature ◽  
Flame Height ◽  
Mixing Efficiency ◽  
Entrainment Rate ◽  
Flame Velocity ◽  
Runge Kutta Method ◽  
Efficiency Parameter ◽  
Entrained Air ◽  
Constant Slope

This paper reports on the determination of the flame height of a flare system using theoretical approach based on the laws of conservation of mass, momentum and energy. The set of ordinary differential equations at steady state conditions are solved numerically by fourth order Runge–Kutta method. The extent of reaction between the fuel and the entrained air has been studied by introducing the reaction mixing efficiency parameter, as the reaction rate is fixed by local entrainment rate. The reaction mixing efficiency parameter is a key measure to determine the height of the flame and its variation with the source velocity is limited by the flame width and the maximum vertical flame velocity at the tip of the flaming region. The variation of different parameters as vertical flame velocity, flame geometry and flame temperature with flame height are shown in plots. It is found that the flame geometry undergoes an initial necking up to a certain height, followed by an increase in its spread thereafter. The flame geometry and the flame dynamics depend exclusively on the burner design and the stack exit velocity. The flame height to burner diameter ratio of the jet diffusion flame is found to vary linearly with Froude number with a constant slope in the logarithmic plot.

Ion Beam Mixing of Ni-Ti Bilayered Thin Films

1985 ◽  
Vol 43 ◽  
pp. 290-291
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Amorphous Alloys ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Mixing Efficiency ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

Morphological behavior of compatibilized ternary blends prepared by mechanical mixing

1993 ◽  
Vol 51 ◽  
pp. 1200-1201
Author(s):  
S.D. Smith ◽  
R.J. Spontak ◽  
D.H. Melik ◽  
S.M. Buehler ◽  
K.M. Kerr ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Diblock Copolymers ◽  
Ternary Blends ◽  
Mechanical Mixing ◽  
Design Considerations ◽  
Covalently Bonded ◽  
Homopolymer Blends ◽  
Emulsifying Agent ◽  
Surface Active ◽  
Low Entropy

When blended together, homopolymers A and B will normally macrophase-separate into relatively large (≫1 μm) A-rich and B-rich phases, between which exists poor interfacial adhesion, due to a low entropy of mixing. The size scale of phase separation in such a blend can be reduced, and the extent of interfacial A-B contact and entanglement enhanced, via addition of an emulsifying agent such as an AB diblock copolymer. Diblock copolymers consist of a long sequence of A monomers covalently bonded to a long sequence of B monomers. These materials are surface-active and decrease interfacial tension between immiscible phases much in the same way as do small-molecule surfactants. Previous studies have clearly demonstrated the utility of block copolymers in compatibilizing homopolymer blends and enhancing blend properties such as fracture toughness. It is now recognized that optimization of emulsified ternary blends relies upon design considerations such as sufficient block penetration into a macrophase (to avoid block slip) and prevention of a copolymer multilayer at the A-B interface (to avoid intralayer failure).

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