Basic calculation method for power of deer antler mixer
In theory, although the mixing power can be divided into two aspects: mixer power and mixing operation power, in practice, only or mainly the mixer power is considered. As it is difficult to accurately measure the mixing operation power, the required mixing operation power is generally achieved by setting the speed of the mixer. Starting from the concept of agitator power, the main factors affecting agitator power are as follows.
① The structure and operating parameters of the agitator, such as the type of agitator, blade diameter and width, blade inclination angle, number of blades, agitator speed, 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 baffles or guide vanes, the width and quantity of baffles, and the diameter of the guide vanes.
③ The physical properties of the medium in the antler mixer, such as the density of each medium, viscosity of the liquid phase medium, size of solid particles, and gas medium permeability.
From the above analysis, it can be seen that the factors affecting stirring power are very complex, and it is generally difficult to directly obtain the calculation equation of stirring power through theoretical analysis methods. Therefore, using experimental methods combined with theoretical analysis is the only way to obtain the formula for calculating stirring power.
By using the Navier Stokes equations in fluid mechanics and representing them in dimensionless form, the dimensionless relationship equations (11-14) can be obtained.
Np=P/ρN³dj5=f（Re，Fr）
Np in the formula - power reference number
Fr - Froude number, Fr=N²dj/g；
P - stirring power, W。
In equations (11-14), the Reynolds number reflects the ratio of fluid inertial force to viscous force, while the Froude number reflects the ratio of fluid inertial force to gravity. Experiments have shown that, except in the transition flow state where Re>300, the Fr number has no effect on the stirring power. Even in the transition flow state where Re>300, the Fr number has little effect on most of the stirring blades. Therefore, in engineering, the power factor is directly expressed as a function of Reynolds number, without considering the influence of Froude number.
Due to the fact that the Reynolds number only includes the speed of the agitator, blade diameter, fluid density, and viscosity, many other factors mentioned above were set in the experiment, and the relationship between the power standard and the Reynolds number was measured. From this, it can be seen that all the relationship curves or equations between power parameters and Reynolds numbers obtained from experiments can only be used within a certain range of conditions. It is obvious that the relationship curve between power accuracy and Reynolds number varies for different blade types, and their Np Re relationship curves will also be different.