The geometric characteristic data of fillers mainly include specific surface area, porosity, filler factor, etc., which are the basic parameters for evaluating filler performance.
(1) Specific surface area The surface area of the filler per unit volume of the filler is called the specific surface area, represented by a, and its unit is m2/m3. The larger the specific surface area of the packing, the larger the gas-liquid mass transfer area provided. Therefore, the specific surface area is an important index to evaluate the performance of the filler.
(2) Porosity The void volume per unit volume of the filler is called porosity, expressed in e, and its unit is m3/m3, or expressed in %. The greater the porosity of the filler, the greater the gas passing capacity and the lower the pressure. Therefore, porosity is another important indicator for evaluating the performance of fillers.
(3) Filler factor The ratio of the specific surface area of the filler to the cubic porosity, namely a/e 3, is called the filler factor, expressed as f, and its unit is 1/m. It represents the hydrodynamic performance of the filler, the smaller the f value, the smaller the flow resistance.