Power Number is a dimensionless parameter based on the power in Watt consumed by the agitating rotor = impellers for the SUB and turbines for the SUF.
How do you calculate the power of an impeller?
Power = Np * n3 * d5 * sg * K The value of the dimensionless power number (Np) depends on several factors including impeller design, number of impellers and location within a tank, tank baffling and fluid viscosity. Typically the power number is shown for mixing in fully turbulent flow.
How is power number calculated?
Power number can be obtained by using the power number curves that are corresponding to the related impellers or calculated by the correlations. The main correlations are the Nagata correlation and Kamei and Himoka correlation to calculate the power number.
How do you calculate Reynolds number for agitator?
Reynolds number for mixing is a defined quantity, which you have identified correctly as Re=rho*D^2*N/mu where D is the agitator diameter and N is RPMs.
How do you size a tank agitator?
In terms of the height of the mixing blade in your tank, the optimal height is to have the blade 1/3 the length of the tank off the bottom of the tank. For example, if you had a tank that was 24 inches tall, you’d want your blade to be 8 inches off the bottom of the tank.
How can I tell the agitator speed?
TipSpeed = Π × D × n
- Tip Speed – impeller tip speed (rpm)
- D – impeller diameter (ft)
- n – impeller rotation speed (fpm)
What is agitator in reactor?
An agitator is a device which is used to import motion in the form of stirring to the liquids or semi solids. The agitator is a device which contains a shaft and an impeller/propeller. The shaft is connected to the gear box and the assembly is driven by motors using electricity.
What is agitator speed?
Agitator designed for low-viscosity products. The speeds available range from 400 to 1,800 rpm, depending on the diameter, with a typical peripheral velocity of between 3 and 15 m/s. According to the agitator’s speed, the agitation system generates a high product recirculation flow rate inside the tank.
What is impeller Reynolds number?
Impeller Reynolds number is by definition the impeller diameter squared times the rotational speed times the liquid density divided by the fluid viscosity. The dimensions of each variable must be consistent or conversion factors must be applied so the result is dimensionless.
What is the easiest way to calculate power?
How is electrical power calculated?
Electrical power is the product of voltage and current. P=VXI.P = V X I .
How do you calculate power in watts?
In other words, watt=amp X volt. Sometimes you will see this formula written as W=A X V. For example, if the current is 3 amps (3A) and the voltage is 110V, you multiply 3 by 110, to get 330W (watts). The formula is P=3A X 110V = 330 W (with P standing for power).
How is Reynolds number calculated?
The Reynolds number (Re) of a flowing fluid is calculated by multiplying the fluid velocity by the internal pipe diameter (to obtain the inertia force of the fluid) and then dividing the result by the kinematic viscosity (viscous force per unit length).
What is flow number in mixing?
The mixing Reynolds number is only a dimensionless number, which represents the flow around the tips of the rotating impeller and ignores the factors affecting the circulating flow throughout the vessel, such as the impeller width and the number of stages of impellers.
How do you calculate agitation scale?
Reynolds number, Froude Number, Power per Volume, Pumping Rate, Pumping Velocity, Scale of Agitation. Reynolds Number: Nre = D x D x N x rho / myu. Pumping Velocity: Vs = Q / A. … S = ( V2 / V1 ) ^ (1/3).
| PARAMETER | SCALING EXPONENT |
|---|---|
| Power per Volume | 2/3 |
| Froude Number | 1/2 |
| Shaft Speed | 0 |
•
What is tank aspect ratio?
Tanks with a 1:1 aspect ratio (straight side length/diameter ratio) provide the most economical industrial agitator design. Tall, skinny tanks can be mixed, but as the aspect ratio increases the blend time becomes much longer at the equivalent power level and agitator cost.
What is pumping factor in agitator?
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.
How do you calculate the RPM of a reactor?
Reactor – 1: L / D = 2 / 1.5 = 1.33, d / D = 1.2 / 1.5 = 0.8, Reactor – 2: L / D = 2.5 / 1.88 = 1.33, d/D = 1.5 / 1.88 = 0.8. So if Reactor – 1 is operated with 48 RPM, then simply adopt 48 RPm to Reactor – 2 also. … Reactors Scale-up:
- Shaft speed,
- Tip speed,
- Reynolds number,
- Froude number,
- Power per unit volume.
What is Zwietering equation?
In using Zwietering’s equation to calculate 𝑆 values, the solids concentration ( 𝑋 ) is given as: 𝑋 𝑥 ( % ) = 𝑥 𝑥 + w a t e r m a s s × 1 0 0 % = 𝑥 + 2 . 6 5 k g × 1 0 0 % , ( 2 ) where 𝑥 is mass of solids in kg.
How many types of agitators are there?
There are two types of Agitators commonly used, 1. Mechanical Agitators, 2. Electronically Controlled Agitators, I’ll demonstrate commonly used Mechanical Agitators.
How do you find power per unit volume?
P/V can be converted from the impeller power number using the following equation: P/V = (Np × p × N³ × d5)/V with Np being the impeller power number, p the density of water (1,000 kg/m³), N the agitation speed (rps), d the impeller outer diameter (m), and V the vessel’s full working volume (m³).
How do you select an agitator in a reactor?
Selection Criteria of Industrial Agitators The viscosity of the bulk. Exact function required (blending, dissolving, dispersion, heat exchange, chemical reaction, crystallization, emulsification, suspension, etc). The mixing cycle (batch size, the time required for agitation, material addition sequence, etc)
What is difference between impeller and agitator?
The Difference Between Agitator vs. Washing machines with agitators use a central post that twists back and forth, rubbing against clothes to help break apart stains. In contrast, washing machines with impellers use a low-profile cone or disc that spins/rotates to rub clothes against each other to get them clean.
What is an agitator motor?
What is critical speed of agitator?
The frequency of the ring depends on the length of the mixer shaft and its elasticity. If you add weight (an impeller) on the end of the mixer shaft, the frequency gets lower. This natural frequency is called the critical speed of the shaft.
What is the maximum speed of propeller mixer in RPM?
Answer: Marine Propeller, Axial Flow Turbine, Turbo Propeller, Flat Blade Turbines, have smaller blade area and these rotate at relatively high speeds (100 to 400 RPM). These are used to mix liquids with low viscosity.
What is agitation scale?
The basic premise of the scale of agitation is that a value of 1 represents the minimum intensity necessary for complete motion of the liquid; a value of 10 represents the maximum practical intensity, although higher intensities might be used for extreme cases.
What is the range of Reynolds number?
Actually, the transition between laminar and turbulent flow occurs not at a specific value of the Reynolds number but in a range usually beginning between 1,000 to 2,000 and extending upward to between 3,000 and 5,000.
What is Reynolds number in fermentation?
Definition. The Reynolds number is the ratio of inertial forces to viscous forces within a fluid which is subjected to relative internal movement due to different fluid velocities.
What is the significance of Reynolds number?
The Reynolds number, referred to as Re, is used to determine whether the fluid flow is laminar or turbulent. It is one of the main controlling parameters in all viscous flows where a numerical model is selected according to pre-calculated Reynolds number.
Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with Sun’Agri and INRAE in Avignon between 2019 and 2022. My thesis aimed to study dynamic agrivoltaic systems, in my case in arboriculture. I love to write and share science related Stuff Here on my Website. I am currently continuing at Sun’Agri as an R&D engineer.