The influence of different structural parameters on mixing in cyclone type mixers was investigated numerically and experimentally utilizing computational fluid dynamics (CFD) and the Iodide Iodate Reaction Method. The hydrodynamics of the mixing processes were investigated numerically. The results indicate the desired swirl motion in the mixing chamber as well as the occurrence of zones of complete recirculation (dead zones) and a zone with the occurrence of cavitation effects. The residence time distribution for a given mixer and mass flow was extracted from the data obtained from numerical simulations. Experimental and numerical results on pressure drop are in very good agreement. The length of the cyclone mixing chamber has only a minor influence on mixing, indicated by the triiodide concentrations of the resulting mixtures. The diameter of the cyclone mixing chamber had a severe effect on mixing. A cyclone mixing chamber with a diameter of 1 mm yields a significantly reduced 'mixing quality' compared to a diameter of 500 mu m ('standard design'). Experimental and numerical data describing mixing could be correlated for mixers with the same internal volume. (C) 2010 Elsevier B.V. All rights reserved.