(1) The surface area of the filler per unit volume of specific surface area is called specific surface area and is expressed in units of m2/m3. The larger the specific surface area of the packing, the larger the gas-liquid mass transfer area provided. Therefore, specific surface area is an important index for evaluating the performance of fillers.
(2) The void volume per unit volume of filler in void volume is called void volume. The void volume in E is expressed as m3/m3, or% of filler. The higher the porosity of the filler, the greater the gas passing capacity and the lower the pressure. Therefore, the porosity is another important index for evaluating the performance of fillers.
(3) The ratio of the specific surface area to the cubic porosity a/e3 of the filler coefficient is called the filler coefficient, which is represented by f and the unit is 1/m. It represents the hydrodynamic properties of the filler. The smaller the f value, the smaller the flow resistance.