ABSTRACT
Geometry analysis of the axial fan impeller, experimentally obtained operating characteristics and experimental investigations of the turbulent swirl flow generated behind the impeller are presented in this paper. Formerly designed and manufactured, axial fan impeller blade geometry (originally designed by Prof. Dr-Ing. Z. Protić†) has been digitized using a threedimensional (3D) scanner. In parallel, the same impeller has been modeled by beta version software for modeling axial turbomachines, based on modified classical calculation. These results were compared. Then, the axial fan operating characteristics were measured on the standardized test rig in the Laboratory for Hydraulic Machinery and Energy Systems, Faculty of Mechanical Engineering, University of Belgrade. Optimum blade impeller position was determined on the basis of these results. Afterwards, the impeller with optimum angle, without outlet vanes, was positioned in a circular pipe. Rotational speed has been varied in the range from 500 till 2500rpm. Reynolds numbers generated in this way, calculated for axial velocity component, were in the range from 0,8·105 till 6·105. LDA (Laser Doppler Anemometry) measurements and stereo PIV (Particle Image Velocimetry) measurements of the 3D velocity field in the swirl turbulent fluid flow behind the axial fan have been performed for each regime. Obtained results point out extraordinary complexity of the structure of generated 3D turbulent velocity fields.
KEYWORDS
PAPER SUBMITTED: 2010-06-17
PAPER REVISED: 2010-07-02
PAPER ACCEPTED: 2010-07-05
THERMAL SCIENCE YEAR
2010, VOLUME
14, ISSUE
Supplement 1, PAGES [S125 - S139]
- Protić Z., Determination of the Dead Water Diameter in Swirl Turbulent Flow in Straight Circular Pipes, (in Serbian language), Proceedings, 10th Yugoslav Congress of Rational and Applied Mechanics, June 1-6., Baško Polje, Yugoslavia, 1970., pp. 429-442
- Protić, Z., Benišek, M., Determination of System Characteristics at Swirling Flow in a Duct Connected with a Fan without Straightening Vanes, (in Serbian language), Proceedings, 15th Yugoslav Congress of Rational and Applied Mechanics, June 1-5., Kupari, Yugoslavia, 1981., B-27, pp. 361-368
- Benišek, M. H., Investigation of the Turbulent Swirling Flows in Straight Pipes, (in Serbian language), Ph. D. thesis, Faculty of Mechanical Engineering, University of Belgrade, Belgrade, Serbia, 1979
- Čantrak, S., Experimental Investigation of the Statistical Properties of Swirling Flows in Pipes and Diffusers, (in German language), Ph. D. thesis, Faculty of Mechanical Engineering, Technical University Karlsruhe, Karlsruhe, Germany, 1981
- Lečić, M. R., Theoretical and Experimental Investigations of the Turbulent Swirling Flows, (in Serbian language), Ph. D. thesis, Faculty of Mechanical Engineering, University of Belgrade, Belgrade, Serbia, 2003
- Čantrak, S., Benišek, M., Nedeljković., M., Lečić M., Problems of Non-Local Turbulent Transfer Modelling, (in German language), ZAMM, (2001), Vol. 81, S4, pp. 913-914
- Čantrak, S. M., Benišek, M. H., Characteristic Magnitudes Determined from Mean Velocity Distributions of Turbulent Swirling Flow in Pipes, ZAMM, (1982), Vol. 62, Issue 4, pp. 201-203
- Strscheletzky, M., Contribution to the Theorem of the Fluid Flow Hydrodinamic Equilibrium, (in German language), Voith Forschung und Konstruktion, Heft 2, Aufstatz 1, (1957)
- Strscheletzky, M., Kinetic Balance Method of the Inner Incompressible Fluid Flows, (in German language), VDI-Z Reihe 7, Nr. 21, Berlin, (1969)
- Eck, B., Fans, Pergamon Press, 1975
- Čantrak, Đ., Ilić, J., Hyde, M., Čantrak, S., Ćoćić, A., Lečić, M., PIV Measurements and Statistical Analysis of the Turbulent Swirl Flow Field, Proceedings, ISFV 13 - 13th International Symposium on Flow Visualization, FLUVISU 12 - 12th French Congress on Visualization in Fluid Mechanics, July 1-4., Nice, France, 2008, CD-ROM, ID 183-0804203
- Ilić, J., Čantrak, Dj., Srećković, M., Laser Sheet Scattering and the Cameras' Positions in Particle Image Velocimetry, Аcta Physica Polonica A, (2007), Vol. 112, No 5., pp. 1113-1118
- Wereley, S.; Gui, L., A Correlation-based Central Difference Image Correction (CDIC) Method and Application in a Four-roll Mill Flow PIV Measurement, Experiments in Fluids, (2003), Vol. 34, pp. 42-51
- Hart, D. P., PIV Error Correction, Experiments in Fluids, (2000), 29, pp. 13-22
- Adrian, R., Dynamic Ranges of Velocity and Spatial Resolution of Particle Image Velocimery, Meas. Sci. Technol., (1997), Vol 8, pp. 1393-1398