Characteristics of the Starting Flow of a Rushton Turbine Mixer

Title & Authors
Characteristics of the Starting Flow of a Rushton Turbine Mixer
Park, Gyeong-Hyeon; Kim, Gyeong-Cheon;

Abstract
The characteristics of starting flow of a six-blade Rushton turbine mixer were investigated by using a cinematic Particle Image Velocimetry technique. The flows were quantified by measurements of velocity fields with a 4 ms time interval for a blade rotational speed of 100 r.p.m, so that the turbine Reynolds number(ND$\small{^2}$/ ν) was fixed to 6,960. The radial shedding of the trailing vortices starts from passing four blades after the beginning of rotation. It clearly shows that the vortex pairing phenomena caused by the interactions between trailing cortices firm consequtive blades. The average convection velocity of the radial flow is found to be 28 % of the tip velocity. The starting flow seems to arrive at a steady state after 8 revolutions in this study, which corresponds nearly one circulation through the bulk flow trajectory with the average radial convection velocity.
Keywords
Rushton Turbine;Starting Flow;Trailing Vortex;Cinematic PIV;Bulk Flow;
Language
Korean
Cited by
1.
러쉬톤 교반기의 초기 비정상 유동 특성,박경현;김경천;

대한기계학회논문집B, 2001. vol.25. 11, pp.1543-1551
References
1.
Yianneskis, M., Popiolek, Z. and Whitelaw, J. H., 1987, 'An Experimental Study of the Steady and Unsteady Flow Characteristics of Stirred Reactors,' J Fluid Mech., Vol. 175, pp. 537 - 555

2.
Distelhoff, M. F. W. and Marquis, A. J., 1998, 'An LIF Line Scan System for the Measurement of Scalar Concentration in a Continuously Operated Stirred Tank,' Experiments in Fluids, Vol. 25, pp, 77-88

3.
김상기, 김경천, 2000, '교반혼합기 내의 거대유동에 대한 PIV 측정,' 대한기계학회 춘계학술대회 초록집 B, pp. 680-685

4.
Riet, K. Vant and Smith, J. M., 1975, 'The Trailing Vortex System Produced by Rushton Turbine Agitators,' Chemical Engineering Science, Vol. 30, pp. 1093-1105

5.
Stoots, C. M., and Calabrese, R. Y., 1995, ''Mean Velocity Field relative to a Rushton Turbine Blade,' AIChE Journal, Vol. 41, No.1, pp. 1- 11

6.
Hart, D. P., 1998, 'The Elimination of Correlation Error in PIV processing,' Proceed of 9th International Symposium on Application of Laser 10 Fluid Mechanics(Lisbon)

7.
Hu, H., Saga, T. and Kobayashi, T., 2000, 'Improve the Spatial Resolution of PlY Results by Using Hierarchical Recursive Operation,' 9th International Symposium on Flow Visualization, Paper number, 137, pp. 1-12

8.
박경현, 김경천, 2001, '고해상도 Cinematic PIV의 개발,' 대한기계학회논문집 B권, 제25권, 제11호, pp. 1535-1542