Theoretically, although the stirring power can be divided into the stirring device power and stirring operation power two aspects of consideration, but in practice generally only consider or mainly consider the mixer power, because the stirring operation power is difficult to accurately determine, generally by setting the speed of the agitator to meet the desired stirring operation power. Starting from the concept of agitator power, the main factors affecting the stirring power are as follows.

(1) The structure and operating parameters of the agitator, such as the type of agitator, the diameter and width of the blade, the angle of the blade, the number of blades, the speed of the agitator, etc.

(2) The structural parameters of the mixing tank, such as the inner diameter and height of the mixing tank, the presence or absence of a bezel or guide cylinder, the width and quantity of the bezel, the diameter of the guide cylinder, etc.

(3) The materiality of the stirring medium, such as the density of each medium, the viscosity of the liquid-phase medium, the size of solid particles, the ventilation rate of the gas medium, etc.

From the above analysis, it can be seen that the factors affecting the stirring power are very complex, it is generally difficult to obtain the calculation equation of stirring power directly through theoretical analysis methods. Therefore, with the help of experimental methods and combined with theoretical analysis, it is the only way to obtain the formula of stirring power calculation.

The Neville-Stokes equation of fluid mechanics is expressed as a scaleless form, which can be obtained in the scaleless relationship (11-14).

Np-P/N-sup3; dj5-f (Re, Fr)

In-type Np-Power Quan

Fr-Froud Number, Fr-N-sup2; dj/g;

P - Stirring power, W.

In the formula (11-14), the Reynolds number reflects the ratio of fluid inertial force to sticky force, while the Freud number reflects the ratio of fluid inertial force to gravity. Experiments show that the Fr number has no effect on the stirring power except in the transition flow state of Re 300. Fr numbers have a significant effect on most of the stirred blades, even in the transition flow state of The Re 300. Therefore, the power factor is expressed directly as a function of the Reynolds number in engineering, regardless of the influence of the Freud number.

Since only the speed of the agitator, the diameter of the blade, the density of the fluid and the viscosity of the fluid are included in the Reynolds number, many other factors mentioned above must be set in the experiment and the relationship between the power count and the Reynolds number can be measured. It can be seen that all the power quasis obtained from the experiment and the Reynolds number of the relationship curve or equation can only be used within a certain range of conditions. The most obvious is that the relationship curve between the power count and the Reynolds number is different, and their Np-Re relationship curve is different.