Power number, which decides power required for mixing, is 1.35 for 3 bladed, 1.4 for 4 bladed, 1.45 for 5 bladed, 1.5 for 6 bladed impeller. Pumping factor, which decides flow rate of mixing, is 0.6 for 3 bladed 0.69 for 4 bladed, 0.78 for 5 bladed, 0.87 for 6 bladed impeller. Diameter of impeller is generally 1/3rd the diameter of the tank
graph below shows the relationship between viscosity and a mixing impellers power response - power draw increases with increasing viscosity. Every impeller has a Power Number vs. Reynolds Number curve similar to the one show below. The straight line portion at the left hand side is the laminar range which develops into the transition
the power number in industrial mixing applications, the power consumption per unit volume of fluid is used extensively for scale-up, scale-down and design. in spite of its widespread use, the dependence of power consumption on impeller and tank geometry is dependent only …
May 01, 2002· Mixing of stabilised drops in suspension polymerisation. Chemical Engineering Science 2004, 59 (11), ... EFFECT OF IMPELLER AND VESSEL SIZE ON IMPELLER POWER NUMBER IN CLOSED VESSELS FOR REYNOLDS NUMBERS BETWEEN 40 AND 65000. Chemical Engineering Communications 1989, 80 (1), ...
Symbol as shown in Fig. 5.19 are as follows:. b—the width of impeller, m.. B W —the width of the baffle, m.. D—the diameter of the mixing chamber, m.. d—the diameter of the impeller, m.. f—the friction coefficient.. H—the height of the liquid level in the mixer, m.. N P —power number.. N P0 —power number without baffle.. N Pmax —power number with baffle.. r—the rotating ...
The present paper deals with the mixing of a highly viscous fluid by close-clearance impellers in cylindrical vessels. The study is performed via numerical simulations. Calculations are achieved by the discretization of continuity and momentum equations with the finite volume method. The effect of blade diameter and its shape on the well-stirred region size and the power consumption is ...
Mixing Impellers by Fusion Power Number Np = 127 Flow Number Nq = 079 This impeller is the workhorse of the mixing industry The simple design of this impeller provides a bination of both radial and axial flow, generates high shear levels, and provides excellent mixing ability. View More Details
Power number constants are listed in Table 2 for the various impeller types shown in Figure 3. Figure 5 and Table 1 are references for the various shape parameters that impact the power number. The example that follows will demonstrate how to determine motor power requirements for …
Shear Rate Variation with Power Number * * Power, flow, and impeller outlet shear rate data were measured in a T390 tank operating in water, tank diameter 390 mm, impeller diameter 160 mm, impeller to tank bottom distance 130 mm, water level 400 mm. The shear rates at the blade surfaces were calculated using Eq.
mixing power consumption the experimental data obtained in this work are graphically presented in coordinates (Poro, Rero) in log-log system in Fig.4. The experimental results presented in Fig.4 suggest that the power number versus the Reynolds number may be described by the following relation Po 120 for Re 42000,78000ro ro=∈( ) (8)
the torque acting on the impeller shaft depends almost entirely on the yield value. Then the power number is approximately correlated by Ny alone.: Np=aNy (22) The resisting force per unit area (F) is shown by Tqc = FbdrnjA (23) where b is paddle width, d is impeller diameter, and np is the number of blades. Eq. (22) and Eq. (23) give
Jun 10, 2012· Power number is dimensionless parameter used for estimating the power consumed by the mixing impeller. For a standard vessel geometry, the power consumed by an impeller at a specified rotational speed, for a liquid with known density, can be determined from the power number correlation. P = N p ρn 3 D a Where
Shear Rate Variation with Power Number * * Power, flow, and impeller outlet shear rate data were measured in a T390 tank operating in water, tank diameter 390 mm, impeller diameter 160 mm, impeller to tank bottom distance 130 mm, water level 400 mm. The shear rates at the blade surfaces were calculated using Eq.
Another dimensionless quantity commonly used to characterize impellers is the power number, NP. It has been shown through experimental data that the power consumption of an impeller, P, is proportional to the cube of the rotational speed of the impeller, the fifth power of the impeller diameter, and the density of the fluid.
Jun 27, 2019· Most radial flow impellers consist of four to six blades. Radial flow impellers are efficient in applications like gas/liquid mixing and dispersion. Selecting An Impeller. Learning how to choose a mixing impeller requires considering a number of different factors that are pertinent to your industry and application. Viscosity
power requirement (turbulent flow) Reynolds number >10000: mixing constant (turbulent flow) fluid mass density: rotation speed revolutions per second (turbulent flow) impeller diameter (turbulent flow)
POWER CONSUMPTION OF AGITATORS >@ (Flow number) 1 tan 3 3 a Q a a a nD q N q nD q K D n k D W v S E S It is a function of the volumetric flow rate and the kinetic energy Values of N Q HE-3 high-efficiency impeller 0.47 Disk turbine 1.3 Four-blade 45q turbine (W/D 0.87 a)=1/6 Marine propellers (square pitch) 0.5 N Q Impeller (Power number) 2 2 2 ...
For two six-blade pitched-blade (45°) turbines, the power is about 1.9 times that of a single pitched-blade impeller. • A baffled, vertical square tank or a horizontal cylindrical tank has the same Power number as a vertical cylindrical tank. SCALE-UP OF MIXING SYSTEMS The calculation of power requirements for agitation is only a part
Figure 1: Power number and pumping number versus impeller Reynold's number for two impeller types. Another useful correlation helps one to maximize the process result by adjusting the D/T ratio. This correlation is again specific for different impeller types and tank geometries
Sep 13, 2018· If all that is needed is a rough estimate, pumping number (Nq) is often related to the power number (Np) of the impeller by a factor times the impeller power number to the one-third power. For axial flow impellers, the pumping number can be approximated by Nq = 0.77 Np^1/3. For radial flow impellers the approximation is Nq = 0.5 Np^1/3.
mixing power consumption the experimental data obtained in this work are graphically presented in coordinates (Poro, Rero) in log-log system in Fig.4. The experimental results presented in Fig.4 suggest that the power number versus the Reynolds number may be described by the following relation Po 120 for Re 42000,78000ro ro=∈( ) (8)
The power number P 0 is therefore constant: (7.3) P 0 = C o n s t a n t = P d 5 N 3 ... In this region, mixing power is proportional to the cube of the rotation speed and to the fifth power of impeller diameter. It is proportional to the fluid density but insensitive to viscosity. In high-power industrial mixers, more than one type of impeller ...
May 01, 2002· Mixing of stabilised drops in suspension polymerisation. Chemical Engineering Science 2004, 59 (11), ... EFFECT OF IMPELLER AND VESSEL SIZE ON IMPELLER POWER NUMBER IN CLOSED VESSELS FOR REYNOLDS NUMBERS BETWEEN 40 AND 65000. Chemical Engineering Communications 1989, 80 (1), ...
Maxflo W blends slightly faster than a P-4 impeller while consuming only about 70 percent of the torque and power. This contrasts to research which suggests that the blend times of two impellers having equal power numbers would produce the same blend times regardless of specific impeller type (ref. 3).
Oct 08, 2008· Nq = Impeller Pumping Number Np = Impeller Power Number Sg = Fluid Specific Gravity: = Fluid Viscosity, cp •Primary Pumping Capacity • Q (gpm) = 4.33 x 10-3 N D3 Nq • Impeller Horsepower Draw •P = 6.556 x 10-14 N3 D5 Sg Np • Impeller Reynold's Number •NRe = 10.7 N D2 Sg / : 49 Impeller Summary •Many different impeller styles ...
Mixing: Impeller performance in stirred tanks. August 2017; ... Po is the impeller' s power number and it is a drag coef-ficient that is determined by the geometry of the impeller