Flow advancement through multi-layered preform with sandwich structure

A new analytic model which can predict location of flow front in the multi-layered preform is proposed. The model includes the contribution of transverse flow between adjacent layers to entire flow through the preform. It is shown that the difference between flow fronts of neighboring layers become constant after sufficient time elapses. To verify the analytic results, numerical flow simulation and experiments are carried out. It is found that when the transverse permeabilities are relatively low, the analytic model underestimates the transverse flow when compared with numerical results. The reason is that the analytic model assumes that the transverse flow occurs only in the flow front region. In this study, effective permeability is analytically calculated and compared with the average permeability which is obtained by applying a simple rule of mixture. (c) 2006 Elsevier Ltd. All rights reserved.