The hydrodynamics inside high solid particle concentration circulating fluidized bed reactor (CFBR) was investigated using computational fluid dynamics simulation (CFDS) and experimental measurement. In order to verify the CFDS obtained results they were compared with the experimental ones by qualitative and quantitative assessments. The CFDS model, with the appropriate initial and boundary conditions, for simulating the high solid particle concentration CFBR were successfully developed, and the obtained results matched with the experimentally-derived ones. Further fluidization regime mapping was performed and the results were summarized based on the statistical parameters of the average solid volume fraction (ASVF) and the standard deviation (SD) of the horizontal and vertical SVFs. The ASVF had a maximum value in the circulating-turbulent fluidization regime, while the SD of the horizontal and vertical SVFs had minimum and maximum values in the bubbling fluidization regime, respectively. As the gas inlet velocity increased, the SD of the SVF tended to approach an invariable value. In addition, the relationships between these three statistical parameters and the positions of the unconventional fluidization regimes (using only primary gas injection) on the general simplified fluidization regime mapping were summarized. (C) 2014 Elsevier Ltd. All rights reserved.