The paper presents the results of model studies on the hydrodynamics of the world's first supercritical circulating fluidized bed boiler Lagisza 460 MWe, carried out on a scale model built in a scale of 1/20 while preserving the full geometrical similarity. To reflect the macroscopic pattern of flow in the boiler's combustion chamber, tests were carried out based on two dimensionless flow dynamic similarity criteria, while maintaining a constant Froude number value between the commercial and the scaled-down units. A mix of polydispersion solids with its fractional composition determined by scaling down the particle size distribution of the boiler's inert material was utilised for the tests using a special scaling function. The obtained results show very good agreement with the results of measurements taken on the Lagisza 460 MWe supercritical CFB boiler.

The article presents the results of laboratory tests carried out on a scaling model of the 966MWth fluidised-bed boiler operating in the Lagisza Power Plant, made on a scale of 1:20 while preserving the geometrical similarity. The tests were carried out for scaled-down material taken from different locations on the circulation contour in the state of full boiler loading. To reflect the hydrodynamic conditions prevailing in the combustion chamber, solids with properly selected density and particle size distribution were used. The obtained results have made it possible to determine the location for taking the most representative granular material sample.

The paper presents an overview of scaling models used for determining hydrodynamic parameters of Circulating Fluidized Bed boilers. The governing equations and the corresponding dimensionless numbers are derived and presented for three different approaches to the scaling law of fluidized beds: classical dimensional analysis, differential equations and integrated solutions and experimental correlations. Some results obtained with these equations are presented. Finally, the capabilities and limitations of scaling experiments are discussed.