scholarly journals Structure of turbulent velocity field in the discharge stream from a standard Rushton turbine impeller

2017 ◽  
Vol 23 (2) ◽  
pp. 151-160 ◽  
Author(s):  
Bohus Kysela ◽  
Jiří Konfrst ◽  
Zdeněk Chára ◽  
Ivan Fořt
Keyword(s):  
Radial Direction ◽  
Laser Doppler Anemometry ◽  
Periodic Part ◽  
Spatial Distributions ◽  
Measurement Point ◽  
Rushton Turbine ◽  
Axial Profile ◽  
Similar Range ◽  
Turbulent Velocity Field ◽  
Turbine Impeller

The radial discharge jet from a standard Rushton turbine was investigated by the Laser Doppler Anemometry (LDA) method. Several distances from the impeller blades (in the radial direction) were chosen for the measurement of axial profiles: all three velocity components (radial, tangential and axial) were measured at each point of the axial profile. The obtained velocity time records were analysed and averaged results were decomposed into three parts: mean ensembleaverage, random and periodic. The ratio of the derived periodic part of the velocity was evaluated in each measurement point and for all velocity components. The obtained results indicate the regions where the periodic part of the velocity has significant effect and where the contribution of this part is almost negligible. Although the values of the periodic part of all velocity components have a rather similar range, the spatial distributions are different in the investigated region.

The flow of liquid in a stream from the standard turbine impeller

1979 ◽  
Vol 44 (3) ◽  
pp. 700-710 ◽  
Author(s):  
Ivan Fořt ◽  
Hans-Otto Möckel ◽  
Jan Drbohlav ◽  
Miroslav Hrach
Keyword(s):  
Reynolds Number ◽  
Kinematic Viscosity ◽  
Momentum Flux ◽  
Relative Size ◽  
Mean Velocity ◽  
Axial Profile ◽  
The Mean ◽  
Hot Film ◽  
Turbine Impeller

Profiles of the mean velocity have been analyzed in the stream streaking from the region of rotating standard six-blade disc turbine impeller. The profiles were obtained experimentally using a hot film thermoanemometer probe. The results of the analysis is the determination of the effect of relative size of the impeller and vessel and the kinematic viscosity of the charge on three parameters of the axial profile of the mean velocity in the examined stream. No significant change of the parameter of width of the examined stream and the momentum flux in the stream has been found in the range of parameters d/D ##m <0.25; 0.50> and the Reynolds number for mixing ReM ##m <2.90 . 101; 1 . 105>. However, a significant influence has been found of ReM (at negligible effect of d/D) on the size of the hypothetical source of motion - the radius of the tangential cylindrical jet - a. The proposed phenomenological model of the turbulent stream in region of turbine impeller has been found adequate for values of ReM exceeding 1.0 . 103.

Effect of Baffle Length on Power Consumption in Turbulent Mixing Vessel with Rushton Turbine Impeller

2011 ◽  
Vol 37 (2) ◽  
pp. 147-149 ◽  
Author(s):  
Yoshihito Kato ◽  
Noboru Kamei ◽  
Yutaka Tada ◽  
Azusa Nakaoka ◽  
Yuichiro Nagatsu ◽  
...  
Keyword(s):  
Power Consumption ◽  
Turbulent Mixing ◽  
Rushton Turbine ◽  
Turbine Impeller

Investigation of turbulent flow field in a Kenics static mixer by Laser Doppler Anemometry

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Halina Murasiewicz ◽  
Zdzislaw Jaworski
Keyword(s):  
Reynolds Number ◽  
Energy Density ◽  
Laser Doppler Anemometry ◽  
Strong Dependence ◽  
Angular Position ◽  
Laser Doppler ◽  
Energy Spectra ◽  
Static Mixer ◽  
Measurement Point ◽  
Velocity Fluctuations

AbstractThe main purpose of the present paper was to apply the Laser Doppler Anemometry (LDA) technique to measure turbulent liquid flow in a Kenics static mixer. The LDA set-up was a one-channel backscatter system with argon-ion laser. Measurements in the static mixer were carried out for three values of the Reynolds number: 5000, 10000, and 18000. Water was used as the process liquid. Values of the axial and tangential components of the local, mean, and root mean square velocities were measured inside the static mixer. It was observed that the shape of the velocity profile depends strongly on the Reynolds number, Re, as well as on the axial, h, and radial, α, position of the measurement point. Strong dependence of the velocity fluctuations on the Reynolds number was found in the investigated range of Re and the measurement point position. Furthermore, one-dimensional energy spectra of the velocity fluctuations were also obtained by means of the Fast Fourier Transform. Fluctuation spectra of the axial and tangential velocities provided information about the energy density of velocity fluctuations in the observed range of Reynolds numbers. A study of the energy spectra led to the conclusion that the energy density increases with the increasing radial distance from the mixer walls at constant values of h, Re, and α. Minor variations in the mean value of the energy density, E, were observed together with variations of the measurement point angular position, α. In addition, it was observed that an increase of the Reynolds number causes significant increase of the power spectral density.

scholarly journals Power Input of High-Speed Rotary Impellers

10.14311/280 ◽  
2001 ◽  
Vol 41 (6) ◽  
Author(s):  
K. R. Beshay ◽  
J. Kratěna ◽  
I. Fořt ◽  
O. Brůha
Keyword(s):  
Pitch Angle ◽  
High Speed ◽  
Power Input ◽  
Cylindrical Vessel ◽  
Turbulent Regime ◽  
Power Dependence ◽  
Rushton Turbine ◽  
Weak Influence ◽  
Turbine Impeller ◽  
Blade Pitch Angle

This paper presents the results of an experimental investigation of the power input of pitched blade impellers and standard Rushton turbine impellers in a cylindrical vessel provided with four radial baffles at its wall under a turbulent regime of flow of an agitated liquid. The influence of the geometry of the pitched blade impellers (pitch angle, number of blades) and the off-bottom impeller clearance of both high-speed impellers tested on the impeller power input is determined in two sizes of the cylindrical vessel (0.3 m and 0.8 m diameter of vessel). A strain gauge torquemeter is used in the small vessel and a phase shift mechanical torquemeter is used in the large vessel. All results of the experiments correspond to the condition that the Reynolds number modified for the impeller exceeds ten thousand. The results of this study show that the significant influence of the separating disk thickness of the turbine impeller corresponds fairly well to the empirical equations presented in the literature. Both the influence of the number of impeller blades and the blade pitch angle of the pitched blade impeller were expressed quantitatively by means of the power dependence of the recently published correlations: the higher the pitch angle and the number of blades, the higher the values of the impeller power input. Finally, it follows from results of this study that the impeller off-bottom clearance has a weak influence on the power input of the Rushton turbine impeller, but with decreasing impeller off-bottom clearance the power input of the pitched blade impeller increases significantly.

scholarly journals CFD Simulation of the Discharge Flow from Standard Rushton Impeller

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Bohuš Kysela ◽  
Jiří Konfršt ◽  
Ivan Fořt ◽  
Zdeněk Chára
Keyword(s):  
Large Eddy Simulation ◽  
Cfd Simulation ◽  
Laser Doppler Anemometry ◽  
Rushton Turbine ◽  
Sliding Mesh ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Mean ◽  
Rushton Impeller ◽  
Good Agreement

The radial discharge jet from the standard Rushton turbine was investigated by the CFD calculations and compared with results from the Laser Doppler Anemometry (LDA) measurements. The Large Eddy Simulation (LES) approach was employed with Sliding Mesh (SM) model of the impeller motion. The obtained velocity profiles of the mean ensemble-averaged velocity and r.m.s. values of the fluctuating velocity were compared in several distances from the impeller blades. The calculated values of mean ensemble-averaged velocities are rather in good agreement with the measured ones as well as the derived power number from calculations. However, the values of fluctuating velocities are obviously lower from LES calculations than from LDA measurements.

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