Unit-time unit area of material circulation or heat flux, such as diffusion flux, Mol-(M2 s), heat flux,/(m2).
The solution of two different concentrations of homogeneous substances is placed adjacent to each other, the solute molecule in the high concentration area will have a net movement to the low concentration area, which is called diffusion. The size of the material molecule's movement, which can be expressed as the number of moles or dinars of a substance that passes through the imaginary plane per square centimeter per second.
Under general conditions, the diffusion flux is proportional to the concentration difference on both sides of the observed plane. If the solution involved is a mixed solution containing a variety of solutes, the direction and flux of each substance is determined only by the concentration difference of the substance, regardless of the concentration or direction of movement of the other substance. However, it should be noted that in the case of an electrolyte solution, the movement of the ions depends not only on the concentration of the ions but also on the electric field forces that the ions are subjected to.
The particle flux n is defined as the increment Dnin of the particle in the time interval DT, and the unit is s-1.
Particle size φ: a point in the radiation field is the number of particles entering the center of the sphere, the cross-section of the ball body in the DA's sphere of the DN divided by the DA's quotient, that is, φ Dond N Da Si units per square metre, (m-2).
Particle injection rate Φ unit time, the number of particles entering the sphere of the unit area is defined as the quotient of D φ divided by DT, and the unit is m-2 • S-1. φ Shand φ Kttad 2n Dadt
Energy injection: The sum of all particle energies (excluding the stationary mass) in the sphere in which the unit cross-sectional area is entered, the unit is J M-2. Chadeefi Da
Energy injection rate of the PSI: unit time into the unit area of all the particles in the body of energy, the Shand Jondr, the unit is J M-2 S-1.
The drying method of the sheet material or the short fibrous material layer is piled on the ventilated floor, and the hot airflow is vertically through the upper or lower part. Compared with the drying method of the heat flow through the material surface, the drying speed is very high due to the large heat transfer coefficient and the increase of the heat transfer area and the decrease of the migration distance between water and steam.