A mathematical model of multi-phase turbulent flow based on the diffusion flux model and the numerical simulation method to analyze the gas-particle flow structures have been developed. The diffusion flux model in which the accelerations due to various forces are taken into account for the calculation of the diffusion velocity of the particles enables its application to the analysis of multi-dimensional gas-particle two-phase flow. In order to verify the accuracy and efficiency of the numerical simulations, an experimental study of gas-particle flow in a suspension bed has been conducted. The numerical analysis results by using the diffusion flux model agree reasonably well with the experimental investigation. It is confirmed that the diffusion flux model has the capacity of correctly simulating the multi-dimensional gas-particle two-phase flow. (C) 2004 Elsevier Ltd. All rights reserved.