A PhD project has been carried out to analyse flow patterns in Fluidised bed reactors using CFD modelling as well as Laser based (LDA/PIV) methods. Both scaled down versions of combustion chambers flows and flow in catalytic crackers has been studied. (Claus H. Ibsen, Bjørn H. Hjertager, Tron Solberg; Vidar Mathiesen, Tel-Tek)