Explain the filtration mechanism of air filter in detail

In the study of inertia mechanism, because the early trajectory calculation is too troublesome, people will borrow the empirical formula sorted out by the calculator, which is common is the "pure inertia" single fiber efficiency without particle size parameters, even if a small number of empirical formulas include particle size parameters, but its scope of application is often very limited. In the study of diffusion mechanism, due to the addition of particle size parameters, but its scope of use is often very limited. In the study of diffusion mechanism, due to the difficulty of integration after adding particle size parameter, a "pure diffusion" single fiber efficiency of zero particle size is obtained. When people have only the calculation formulas of pure inertia and pure diffusion available, and also consider the influence of dust size, they take it for granted that the "ideal interception" with neither inertia nor diffusion is a separate filtration mechanism parallel to inertia and diffusion. People often add pure inertia, pure diffusion and ideal interception to calculate the combined single-fiber efficiency, and some researchers add or subtract some corrections from the three.

In the air filter, the inertia and diffusion collision of dust occur at the same time, and sometimes other filtration mechanisms also play a role, such as static electricity, gravitational sedimentation, screen resistance, etc. However, in theoretical research, due to mathematical difficulties, it is difficult to incorporate the parameters of several mechanisms into a mathematical model to calculate, so various filtration mechanisms are studied separately to find out the single fiber efficiency under the action of a single mechanism, and then some method is used to combine the single fiber efficiency of two or several mechanisms. In order to approximate the single fiber efficiency under the combined action of tree species mechanism. Various methods of combining single fiber efficiency in previous literature are recorded.

In the first two chapters dealing with inertia and diffusion, we have seen that the so-called ideal interception is nothing more than a mathematical limit case. If the influence of dust size has been taken into account in the derivation of various mechanisms. Ideal interception should no longer be classified as a separate filtration mechanism, at least not on a par with inertia and diffusion.