Energy dissipation rate in a baffled vessel with pitched blade turbine impeller

1991 ◽  
Vol 56 (9) ◽  
pp. 1856-1867 ◽  
Author(s):  
Zdzisław Jaworski ◽  
Ivan Fořt
Keyword(s):  
Energy Dissipation ◽  
Cross Sections ◽  
Mechanical Energy ◽  
Vessel Diameter ◽  
Energy Dissipation Rate ◽  
Mean Velocity ◽  
Agitated Vessel ◽  
Radial Profiles ◽  
Pitched Blade Turbine ◽  
Turbine Impeller

Mechanical energy dissipation was investigated in a cylindrical, flat bottomed vessel with four radial baffles and the pitched blade turbine impeller of varied size. This study was based upon the experimental data on the hydrodynamics of the turbulent flow of water in an agitated vessel. They were gained by means of the three-holes Pitot tube technique for three impeller-to-vessel diameter ratio d/D = 1/3, 1/4 and 1/5. The experimental results obtained for two levels below and two levels above the impeller were used in the present study. Radial profiles of the mean velocity components, static and total pressures were presented for one of the levels. Local contribution to the axial transport of the agitated charge and energy was presented. Using the assumption of the axial symmetry of the flow field the volumetric flow rates were determined for the four horizontal cross-sections. Regions of positive and negative values of the total pressure of the liquid were indicated. Energy dissipation rates in various regions of the agitated vessel were estimated in the range from 0.2 to 6.0 of the average value for the whole vessel. Hydraulic impeller efficiency amounting to about 68% was obtained. The mechanical energy transferred by the impellers is dissipated in the following ways: 54% in the space below the impeller, 32% in the impeller region, 14% in the remaining part of the agitated liquid.

Hydraulic characteristics of turbine impeller

1982 ◽  
Vol 47 (2) ◽  
pp. 421-429 ◽  
Author(s):  
Ivan Fořt ◽  
Jana Malá
Keyword(s):  
Mechanical Energy ◽  
Volumetric Flow Rate ◽  
Vessel Diameter ◽  
Diameter Ratio ◽  
Turbulent Regime ◽  
Hydraulic Efficiency ◽  
Hydraulic Characteristics ◽  
Total Head ◽  
Turbine Impeller

The study concentrates on the determination of hydraulic characteristics (volumetric flow rate, power output, hydraulic efficiency and total head) of a standard, six-blade turbine impeller in a flat-bottomed cylindrical vessel provided with radial baffles at a turbulent regime of agitated liquid. The investigated characteristics are determined by means of a macroscopic balance of mechanical energy of the impeller region expressed in a dimensionless form. The results show that all the hydraulic characteristics investigated, with the exception of the dimensionless impeller total head, are independent of the impeller-to-vessel diameter ratio. The hydraulic efficiency of a standard turbine impeller is about 40%.

Energy Dissipation Rate Control for Planar Biped Walking Robot Based on the Property of Passive Dynamic Walking

2014 ◽  
Author(s):  
Mohsen Azimi ◽  
M. R. Hairi Yazdi
Keyword(s):  
Energy Dissipation ◽  
Dissipation Rate ◽  
Mechanical Energy ◽  
Main Idea ◽  
Energy Dissipation Rate ◽  
Dynamic Walking ◽  
Walking Robot ◽  
Passive Dynamic Walking ◽  
Biped Walking ◽  
Biped Walking Robot

Several control methods based on passive dynamic walking have been proposed by researchers to provide an efficient human-like biped walking robot. For most of these passive based controllers the main idea is to shape the robot’s energy level during each Single Support Phase (SSP) to restore the mechanical energy which has been lost in the previous Impact Phases (IP). In this paper, instead of controlling the energy restoration rate during each SSP, a new strategy is introduced which provides a stable walking by controlling the energy dissipation rate during each IP. Subsequently, this method is applied to an anti-trunk biped robot with lockable knee joints to realize an active dynamic walking on level ground. Simulation results show, the proposed method is effective.

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.

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