Pseudo two dimensional (pseudo 2D) fluidized beds, for which the thickness of the system is much smaller than the other two dimensions, are widely used to perform fundamental studies on bubble behavior, solids mixing, or clustering phenomenon in different gas solids fluidization systems. The abundant data from such experimental systems are very useful for numerical model development and validation. However, it has been reported that two-dimensional (2D) computational fluid dynamic (CFD) simulations of pseudo 2D gas solids fluidized beds usually predict poor quantitative agreement with the experimental data, especially for the solids velocity field. In this paper, a new model is proposed to improve the 2D numerical simulations of pseudo 2D gas solids fluidized beds by properly accounting for the frictional effect of the front and back walls. Two previously reported pseudo 2D experimental systems were simulated with this model. Compared to the traditional 2D simulations, significant improvements in the numerical predictions have been observed and the predicted results arc in better agreement with the available experimental data. (C) 2013 Elsevier Ltd. All rights reserved.