(62d) Stereoscopic PIV Study on Swirl Phenomena in Uniflow Cyclones

Understanding the complex flow field in a uniflow cyclone is important for further design development. The uniflow cyclone is advantageous in certain applications due to the compactness e.g. in space-limited environments in engineering equipment and will be therefore investigated. This separator type uses centrifugal forces induced by a swirl vane inlet to separate particles from a continuous phase. The resulting flow field is characterized by a strong circumferential velocity component, which forces the fluid to rotate in downstream direction.

Stereo-PIV is used to evaluate the flow field along the cross section and to gain insights into the flow field characteristics [1]. 3C/2D-PIV is is applied to evaluate all three velocity components simultaneously in the measurement plane. Therefore the cameras and the laser optics are mounted on an 1D traversing mechanism for precise positioning of the optical PIV system in the measurement volume along the axis of the main flow. This study mainly focuses attention on detailed measurements on the flow field in the separation chamber of the uniflow cyclone to find the best geometric parameters by means of aerodynamic aspects [2,3]. For validation a set of dust-laden experiments are carried out to get information about separation efficiency and pressure drop (ISO 5011) [4]. As a result the effect on cyclone performance has been quantified with a consistent set of experimental data which shows the influence of vane angle and core diameter ratio variations.

[1] Pillei, M., Goller, R., Kofler, T., Wierschem, A., and Kraxner, M., “Experimental Investigation of the Velocity Distribution near the Swirl Generator of a Uniflow Cyclone for Performance Data Prediction,” In 18th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics.

[2] Chang, F. and Dhir, V. K., “Turbulent flow field in tangentially injected swirl flows in tubes,” International Journal of Heat and Fluid Flow, vol. 15, no. 5, pp. 346–356, 1994

[3] Pillei, M.; Kofler, T.; Kraxner, M.; Fluid flow investigation in the separation chamber of a uniflow cyclone with 3C-PIV and CFD; Fachtagung “Lasermethoden in der Strömungsmesstechnik”; GALA Karlsruhe, 2014.

[4] ISO 5011. Inlet air cleaning equipment for internal combustion engines and compressors - Performance testing.