Fluid permeation resistance through a particle-packed bed with a non-uniform structure was investigated both theoretically and experimentally to confirm the relationship between pressure drop and air flow rate. Multiple-block construction consisting of various types of powders in the particle bed was used in this experiment. With the goal of design and operation simplification. a model bed was used to simulate an actual powder bed with a non-uniform structure due to local variation in particle size, particle shape and packing density. An electrical network circuit analogy was used to express the theoretical model bed where fluid flows in a zigzag manner among particles in the bed. The results showed good agreement between the theoretical model and experimental data. The results also verified that the fluid flow was irregular in all directions when using the non-uniform structure. In addition, the present study demonstrated that the concept of "tortuosity" should be considered due to the irregular flow path in the bed. Thus, the results of the present study suggest that the electric resistance network analogy might be useful in solving the problem of fluid permeation in actual particle layers with non-uniform structures. (C) 2008 Elsevier B.V. All rights reserved.