Flow duct with cross-sectional step

摘要

In heat generators and burners, it is frequently necessary to realize discontinuous cross-sectional expansions of a flow duct. When the flow (U) passes over the step (10) formed in the wall (8) of the flow duct, coherent lateral separation vortices form which are propagated almost undamped downstream of the step and frequently represent the cause of thermo-acoustic vibrations of high amplitude. In accordance with the invention, vortex-generating elements (20) with a lateral pitch dimension (t) are arranged on a line transverse to the main flow (U) a distance (s) upstream of the step (10). Given an expedient selection of the pitch dimension (t), the lateral coherence of the separation vortex is enduringly destroyed.