Abstract
Permeability of seven kinds of JIS Test Powder beds was measured with N2 gas converted to the specific surface area of powder using various Rigden-type permeability equations including Kozeny-Carman equation.
Kozeny-Carman equation without molecular flow permeation was applicable only to powders coarser than about 10μm.
The experimental results with finer powders suggested that other permeation equations with proper evaluation of molecular flow mechanism should be used and that incorrect evaluation of molecular flow would cause certain non-linear error in the calculated surface area.
Experimental trials to seek an optimal value of the weight coefficient of molecular flow term in Rigden-type equation suggested that the value might be smaller than the Rigden's value, 0.515, which had been the smallest among the proposed value. Further careful study should be done because this result seemed to be too small and might be erroneous due to some experimental errors such as agglomeration and segregation during preparation of powder mixture.
