(421s) Investigations to the Particle Movement inside Swirl Vanes to Increase the Separation Efficiency of Uniflow Cyclones

Abstract

Uniflow cyclones used for separation have gas and particles passing through them in only one direction. They are characterized - compared to the standard reverse flow cyclone - by a compact design, a low pressure drop and the ability to easy retrofit into existing piping systems. The scope of this investigation is to describe the flow pattern in a standard swirl generator and a new geometrical design approach of a uniflow cyclone to increase the collection efficiency and decrease the pressure drop [1,2]. The swirl generator consists of several curved blades arranged circular around a cylindrical core and is responsible for the swirl (centrifugal forces) and therefore for the separation of the particles. Preliminary dedusting tests presented on the AIChE 2012 Annual Meeting show a significant optimization potential [3]. For further investigations dedusting test were made and to examine the flow field particle image velocimetry (2C-PIV) measurements and CFD simulations have been carried out. To reduce the experimental effort a sensitivity study has been performed to identify tendencies. The observed characteristics are the collection efficiency, the pressure drop and the velocity distribution.

The results show that an alternating shortening of the guide vanes leads to a detachment of the flow at the backside of the shortened vanes [4]. This phenomenon minimizes the cross-section area for the flow and increases the velocity within the vane channel. The un-shortened vane is responsible for a smooth transition of the flow from the inlet section into the vane channel and therefore for a nearly constant pressure drop. The particle tracking via High-Speed camera should show the influence of the vane design on the movement of the particle inside the vane channel and further on the cyclone efficiency.

[1]            Muschelknautz, U., Zyklone zum Abscheiden fester Partikel aus Gasen, LCD. VDI Wärmeatlas, 2006.

[2]            Hoffmann, A.C., Stein, L.E., Gas Cyclones and Swirl Tubes - Principles, Design and Operation. Berlin, Heidelberg: Springer, 1. au. ed., 2002.

[3]            Kraxner, M., Muschelknautz, U., Wechner, S., Ackermann, S., Greif, V., Bolda, J., Influence of the Inlet Vane Geometry On the Uniflow Cyclones Performance (639f). AIChE 2012 Annual Meeting, 2012.

[4]            Kraxner, M., Empirische Ermittlung von Auslegungskriterien für Gleichstromzyklone in Multizyklonblöcken, Dissertation, TU München, 2013.