Impeller blade width

For multiple turbines (/ in number) the sum of impeller blade widths X should be used for W, and the average impeller height X 67// should be used for Cin the equations which include these terms. With turbines having different diameters on the same shaft, a weighted average diameter based on the exponents of in the appropriate equations should be used. 

When macro-scale variables are involved, every geometric design variable can affect the role of shear stresses. They can include such items as power, impeller speed, impeller diameter, impeller blade shape, impeller blade width or height, thickness of the material used to make the impeller, number of blades, impeller location, baffle location, and number of impellers. 

H = total potential head during flow, ft P = power, ft-lb/sec W = impeller blade width, ft l = viscosity, lb/ft-sec p = density, pounds/cu ft Ns = revolutions/sec... 

W = Physical depLh or height of turbine mixer, ft or in., consistent with other dimensions, Figure 5-34 or, W = Impeller blade width, ft... 

Proportions of a stirred tank relative to the diameter D liquid level = D turbine impeller diameter = D/3 impeller level above bottom = D/3 impeller blade width = D/15 four vertical baffles with width = D/10. 

Geometrical dimensions of the system Suppose that we use a baffled cylindrical vessel and a flat-blade turbine with six blades. Given that the volume of the liquid to be treated VL = 100 L and using the analogies and equations of Section 3.3.5, we obtain impeller diameter Da = 16.77 cm, vessel diameter DT = 50.32 cm, impeller blade width W = 3.35 cm, liquid level Hh = 50.32 cm, impeller level above the bottom equal to 16.77 cm, and B = 2.8 cm. Finally, it is desirable to use a vessel height HT somewhat higher than the... 

New nomenclature da is outside tube diameter of coil, Dc is coil diameter, tiby is number of vertical baffle-type coils, Sc is coil spacing, W is impeller blade width, and Zt is height of coil from tank bottom. 

Taguchi and Miyamoto (1966) showed that for non-Newtonian fermentation broth, the power requirement in the turbulent flow regime was well correlated by the above correlation of Michel and Miller (1962). Broth from the production of gluco-amylase by Endomyces species and carboxymethyl-cellulose solutions were used as non-Newtonian fluids. For non-Newtonian fluids in laminar and transition regions, particularly for fluids with apparent viscosities greater than 300 cP, the impeller diameter and impeller blade width had considerable effects on power consumption in a non-gassed system. They proposed... 

The first term in parentheses refers to the value of the impeller diameter, D the second is the impeller blade width, B. 

The integral length scales or macro scales of turbulence are generally of the same order of magnitude as the impeller blade width. In addition, the macro scale of turbulence is found to scale with the impeller size. This means that for a large scale vessel, larger eddies will form than in a small vessel. Consequently, large variations in velocities and concentrations can be expected in the vessel upon scale-up. 

The power number, Np, also is a function of impeller blade width, number of blades, blade angle, D/T, baffle configuration and impeller elevation. Figure 6-14 shows the relationship between Np and Re for seven impellers. It is important to recognize that at Re < 100, the conditions become laminar flow and mixing quality, obtained using these impellers, becomes extremely poor. Under such conditions, impellers designed for laminar flow conditions are reconunended. 

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