JFCMV  Vol.4 No.1 , January 2016
Effect of Axial Clearance on the Flow Structure around a Rotating Disk Enclosed in a Cylindrical Casing
Abstract: Numerical study is performed to investigate the swirling flow around a rotating disk in a cylindrical casing. The disk is supported by a thin driving shaft and it is settled at the center of the casing. The flow develops in the radial clearance between the disk tip and the side wall of the casing as well as in the axial clearance between the disk surfaces and the stationary circular end walls of the casing. Keeping the geometry of the casing and the size of the radial clearance constant, we compared the flows developing in the fields with small, medium and large axial clearances at the Reynolds number from 6000 to 30,000. When the rotation rate of the disk is small, steady Taylor vortices appear in the radial clearance. As the flow is accelerated, several tens of small vortices emerge around the disk tip. The axial position of these small vortices is near the end wall or the axial midplane of the casing. When the small vortices appear on one side of the end walls, the flow is not permanent but transitory, and a polygonal flow with larger several vortices appears. With further increase of the rotation rate, spiral structures emerge. The Reynolds number for the onset of the spiral structures is much smaller than that for the onset of the spiral rolls in rotor-stator disk flows with no radial clearance. The spiral structures in the present study are formed by the disturbances that are driven by a centrifugal instability in the radial clearance and they are penetrated radially inward along the circular end walls of the casing.
Cite this paper: Watanabe, T. , Furukawa, H. , Fujisawa, S. and Endo, S. (2016) Effect of Axial Clearance on the Flow Structure around a Rotating Disk Enclosed in a Cylindrical Casing. Journal of Flow Control, Measurement & Visualization, 4, 1-12. doi: 10.4236/jfcmv.2016.41001.

[1]   Launder, B., Poncet, S. and Serre, E. (2010) Laminar, Transitional and Turbulent Flows in Rotor-Stator Cavities. Annual Review of Fluid Mechanics, 42, 229-248.

[2]   Viaszzo, S., Poncet, S., Serre, E., Randriamampianina, A. and Bontoux, P. (2012) High-Order Large Eddy Simulation of Confined Rotor-Stator Flows. Flow Turbulence and Combustion, 88, 63-75.

[3]   Schouveiler, L., Le Gal, P. and Chauve, M.P. (2001) Instabilities of the Flow between a Rotating and a Stationary Disk. Journal of Fluid Mechanics, 443, 329-350.

[4]   Savas, Ö. (1987) Stability of Bödewadt Flow. Journal of Fluid Mechanics, 183, 77-94.

[5]   Tuliska-Sznitko, E., Serre, E. and Bontoux, P. (2002) On the Nature of the Boundary Layers Instabilities in a Flow between a Rotating and a Stationary Disc. C.R.Mecanique, 330, 91-99.

[6]   Cros, A. and Le Gal, P. (2002) Spatiotemporal Intermittency in the Torsional Couette Flow between a Rotating and a Stationary Disk. Physics of Fluids, 14, 3755-3765.

[7]   Schouveiler, L., Le Gal, P., Chauve, M.P. and Takeda, Y. (1999) Spiral and Circular Waves in the Flow between a Rotating and a Stationary Disk. Experiments in Fluids, 26, 179-184.

[8]   Cros, A., Floriani, E., Le Gal, P. and Lima, R. (2005) Transition to Turbulence of a Batchelor Flow in a Rotor/stator Device. European Journal of Mechanics B/Fluid, 24, 409-424.

[9]   Lopez, J.M., Marques, F., Rubio, A.M. and Avila, M. (2009) Crossflow Instability of Finite Bödewadt Flows: Transitions and Spiral Waves. Physics of Fluids, 21, 114107-1-9.

[10]   Poncet, S., Serre, é. and Le Gal, P. (2009) Revisiting the Two First Instabilities of the Flow in an Annular Rotor-Stator Cavity. Physics of Fluids, 21, 064106-1-8.

[11]   Spohn, A., Mory, M. and Hopfinger, E.J. (1998) Experiments on Vortex Breakdown in a Confined Flow Generated by a Rotating Disk. Journal of Fluid Mechanics, 370, 73-99.

[12]   Meeuwse, M., van del Schaaf, J. and Schouten, J.C. (2012) Multistage Rotor-Stator Spinning Disc Reactor. AIChE Journal, 58, 247-255.

[13]   Schouveiler, L., Le Gal, P. and Chauve, M.P. (1998) Stability of a Traveling Roll System in a Rotating Disk Flow. Physics of Fluids, 10, 2695-2697.

[14]   Al-Shannag, M., Herrero, J., Humphrrey, J.A.C. and Giralt, F. (2002) Effect of Radial Clearance on the Flow between Corotating Disks in Fixed Cylindrical Enclosures. Transactions of ASME, Journal of Fluids Engineering, 124, 719- 727.

[15]   Hendriks, F. (2010) On Taylor Vortices and Ekman Layers in Flow-Induced Vibration of Hard Disk Drives. Microsystem Technologies, 16, 93-101.

[16]   Washizu, T., Lubisch, F. and Obi, S. (2013) LES Study of Flow between Shrouded Co-Rotating Disks. Flow Turbulence and Combustions, 91, 607-621.

[17]   Benjamin, T.B. and Mullin, T. (1981) Anomalous Modes in the Taylor Experiment. Proceedings of Royal Society of London, Series A, 377, 221-249.

[18]   Rucklidge, A.M. and Champneys, A.R. (2004) Boundary Effects and the Onset of Taylor Vortices. Physica D, 191, 282-296.

[19]   Watanabe, T. and Furukawa, H. (2010) Flows around Rotating Disks with and without Rim-Shroud Gap. Experiments in Fluids, 48, 631-636.

[20]   Watanabe, T. and Furukawa, H. (2010) The Effect of Rim-Shroud Gap on the Spiral Rolls Formed around a Rotating Disk. Physics of Fluids, 22, Article ID: 114107.

[21]   Hara, S., Watanabe, T., Furukawa, H. and Endo, S. (2015) Effects of a Radial Gap on Vortical Flow Structures around a Rotating Disk in a Cylindrical Casing. Journal of Visualization, 18, 501-510.

[22]   Séverac, é., Poncet, S. and Serre, é. (2007) Large Eddy Simulation and Measurements of Turbulent Enclosed Rotor- Stator Flows. Physics of Fluids, 19, Article ID: 085113.

[23]   Serre, E., Crespo Del Arco, E. and Bontoux, P. (2001) Annular and Spiral Patterns in Flows between Rotating and Stationary Discs. Journal of Fluid Mechanics, 434, 65-100.

[24]   Watanabe, T., Furukawa, H. and Nakamura, I. (2002) Nonlinear Development of Flow Patterns in an Annulus with Decelerating Inner Cylinder. Physics of Fluids, 14, 333-341.

[25]   Wu, S.C. (2009) A PIV Study of Co-rotating Disks Flow in a Fixed Cylindrical Enclosure. Experimental Thermal and Fluid Science, 33, 875-882.

[26]   Huang, R.F. and Hsieh, M.K. (2011) Phase-Resolved Flow Characteristics between Two Shrouded Co-Rotating Disks. Experiments in Fluids, 51, 1529-1547.

[27]   Lim, T.T., Chew, Y.T. and Xiao, Q. (1998) A New Flow Regime in a Taylor-Couette Flow. Physics of Fluids, 10, 3233-3235.

[28]   Koschmieder, E.L. (1993) Bénard Cells and Taylor Vortices. Cambridge University Press, Cambridge.

[29]   Cole, J.A. (1976) Taylor-Vortex Instability and Annulus-Length Effect. Journal of Fluid Mechanics, 75, 1-15.