Observation of permeability dependence on flow rate and implications for liquid composite molding

The variation of permeability with the flow rate has been investigated. This variation is demonstrated by conducting specially designed experiments. The results show that permeability increases significantly as the flow rate increases. The implication of this observation is that the permeability measured under some given conditions is not always applicable to the actual molding situation. Furthermore, the permeability is not constant over both the space and time domains during the filling process. In order to take such dependence into account, a permeability model and an estimation technique for determining the coefficients of the model are proposed.