macroscopic model, based on the volume-averaged equations of momentum and continuity, is presented to predict hydrodynamic characteristics of gas and liquid countercurrent flow in random packed columns. The main advantage of this approach is that the model equations derived from the mass and momentum conversation laws will remain valid on a wider range of length scale, from laboratory to industrial size packed columns. Therefore they can be used as basic tool for more rigorous design and scale up of packed columns. In this study, the large-scale liquid maldistribution was simulated using the proposed model for a 0.6-m diameter column packed with 25 min stainless steel Pall rings. The development of liquid flow patterns along the packed height was obtained for several different initial distributions of liquid phase. Furthermore, the effect of liquid and gas loads on the liquid distribution was examined. The simulation results are in good agreement with the experimental data obtained in our laboratory for both water/air and isopar/air systems.