Experimental investigation of flow pattern in enhanced exchangers with active insert devices

Abstract

The present paper studies the flow features induced by a mechanically assisted device inserted in a round tube. The reciprocating movement of the active insert device generates macroscopic displacements of the flow, increasing heat transfer. At the same time, the insert device scraps the inner tube wall, avoiding fouling. Particle Image Velocimetry technique has been employed to obtain the velocity field over a symmetry plane. In static conditions, two flow features have been identified, as well as its evolution for a range of Reynolds number between 44 and 369. In dynamic conditions, the flow conditions for Re=44 and two different scraping velocities have been studied. The flow features for the two stages of the scraping cycle have been identified, revealing higher velocity distributions than in the static condition.