Experimental Investigation of Flow Induced Rotor Oscillations in a Centrifugal Sewage Water Pump

Volume 3 ◽  
2004 ◽  
Author(s):  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen ◽  
Oliver Schneider
Keyword(s):  
Experimental Investigation ◽  
Static Pressure ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Sewage Water ◽  
Water Pump ◽  
Flow Rates ◽  
Pump Rotor ◽  
Pump Shaft ◽  
Impeller Geometry

Most of the pumps for sewage transport have a special impeller geometry in order to avoid operational disturbances by clogging. The almost exclusively used single stage machines particularly are equipped with single-blade impellers. With this impeller geometry a strongly uneven pressure field along the perimeter of the pump casing can be expected. The resulting periodically unsteady flow forces affect the impeller and produce strong radial deflections of the pump shaft. In this contribution the experimental investigation of the dynamic behavior of the pump rotor as a consequence of the transient hydrodynamic forces is described. To verify the calculated rotor oscillations measurements were performed at several rotating speeds and at different volume flow rates. The pump which before has been investigated numerical was equipped with several sensors. The deflections of the pump rotor were measured with two proximity sensors. The measurement of the vibration accelerations at the pump casing showed the effects of the transient hydrodynamic stimulation forces. Measurements of the static pressure in the casing allowed a correlation between the rotor oscillations and the pressure fluctuations produced by the single-blade impeller.

Measurement of Flow Induced Rotor Oscillations in a Single-Blade Centrifugal Pump

2004 ◽  
Author(s):  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen ◽  
Oliver Schneider
Keyword(s):  
Static Pressure ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Sewage Water ◽  
Volume Flow ◽  
Flow Rates ◽  
Pump Rotor ◽  
Simultaneous Measurements ◽  
Pump Shaft ◽  
Impeller Geometry

The composition of sewage water with partially large portions of fibers and solids requires a special impeller geometry, in order to avoid operational disturbances of the pump by clogging. Therefore the almost exclusively used single stage machines particularly are equipped with single-blade impellers. The rotation of the impeller in the pump casing produces a strongly uneven pressure field along the perimeter of the casing. The resulting periodically unsteady flow forces affect the impeller and produce radial deflections of the pump shaft which can be recognized as vibrations at the bearing blocks or at the pump casing [1]. In this contribution the experimental investigation of the dynamic behavior of a pump rotor under the influence of the flow forces is described. To verify calculated results performed earlier a lot of measurements have been carried out at several speeds of rotation and at different volume flow rates. The pump which before was investigated numerical had been equipped with several sensors. The deflections of the pump rotor were measured with two proximity sensors and compared to the computed amounts. Measurements of the static pressure in the casing gave the connection between the rotor oscillations and the pressure fluctuations produced by the single-blade impeller. The simultaneous measurements of the vibration velocities and accelerations at the pump casing showed the effects of the transient hydrodynamic stimulation forces.

scholarly journals An Experimental Study on the Fluid Forces Induced by Rotor-Stator Interaction in a Centrifugal Pump

2003 ◽  
Vol 9 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Shijie Guo ◽  
Hidenobu Okamoto
Keyword(s):  
Centrifugal Pump ◽  
Static Pressure ◽  
Pressure Fluctuations ◽  
Strong Relationship ◽  
Operating Conditions ◽  
Flow Rates ◽  
Fluid Forces ◽  
Large Pressure ◽  
Rotor Stator Interaction ◽  
Frequency Components

The pressure fluctuations and the radial fluid forces acting on the impeller, the pressures in the volute, as well as the vibration of the shaft in a centrifugal pump were measured simultaneously, and their relationship was investigated. Experiments were done for various diffuser vanes, flow rates, and rotating speeds. It was demonstrated that both the blade-pressure fluctuations and the volute static pressures are nonuniform circumferentially (not axisymmetrical) under off-design operating conditions and that the two have a strong relationship. At high flow rates, the blade pressure fluctuations, induced by rotor-stator interactions, are large in areas where the volute static pressure is low. The traveling directions of the rotating pressure waves, the whirling directions of the radial fluid forces, and the most predominant frequency components of both the fluctuations and the forces are discussed, and an equation for predicting them is introduced. It was also noted that large alternating fluid forces are not necessarily associated with large pressure fluctuations. Furthermore, when measuring the radial fluid forces in the rotating frame, other frequency components, in addition to those related to the products of the diffuser vane number and the rotating frequency, may occur due to the circumferential unevenness of the pressure fluctuations on the impeller. These components are predictable.

Air to Air Ejector with Various Divergent Mixing Chambers

2014 ◽  
Vol 493 ◽  
pp. 50-55
Author(s):  
Václav Dvořák
Keyword(s):  
Experimental Investigation ◽  
Static Pressure ◽  
Pressure Fluctuations ◽  
Mixing Process ◽  
Mixing Processes ◽  
Process Characteristics ◽  
Pressure Distributions ◽  
Mixing Chamber ◽  
Air Ejector ◽  
Mixing Chambers

The article deals with experimental investigation of subsonic air to air ejector with various configurations of the mixing chamber and the diffuser. A constant mixing chamber, 2° and 4° divergent mixing chambers and 6° diffuser were applied to find differences in the mixing process. Characteristics of the ejector, static pressure distributions and pressure fluctuations were measured to find how the different shape of the mixing chamber affect the efficiency of mixing processes. Pressure fluctuation increased rapidly while the ejection ratio was higher than 1.25 and the highest efficiency of the ejector was obtained when using configuration 4-4-6.

Effect of Clocking on the Second Stator Pressure Field of a One and a Half Stage Transonic Turbine

2004 ◽  
Author(s):  
J. Gadea ◽  
R. De´nos ◽  
G. Paniagua ◽  
N. Billiard ◽  
C. H. Sieverding
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Leading Edge ◽  
Fast Response ◽  
Time Resolved ◽  
Pressure Transducers ◽  
Static Pressure Distribution ◽  
Transonic Turbine

This paper focuses on the experimental investigation of the time-averaged and time-resolved pressure field of a second stator tested in a one and a half stage high-pressure transonic turbine. The effect of clocking and its influence on the aerodynamic and mechanical behaviour are investigated. The test program includes four different clocking positions, i.e. relative pitch-wise positions between the first and the second stator. Pneumatic probes located upstream and downstream of the second stator provide the time-averaged component of the pressure field. For the second stator airfoil, both time-averaged and time-resolved surface static pressure fields are measured at 15, 50 and 85% span with fast response pressure transducers. Regarding the time-averaged results, the effect of clocking is mostly observed in the leading edge region of the second stator, the largest effects being observed at 15% span. The surface static pressure distribution is changed locally, which is likely to affect the overall performance of the airfoil. The phase-locked averaging technique allows to process the time-resolved component of the data. The pressure fluctuations are attributed to the passage of pressure gradients linked to the traversing of the upstream rotor. The pattern of these fluctuations changes noticeably as a function of clocking. Finally, the time-resolved pressure distribution is integrated along the second stator surface to determine the unsteady forces applied on the vane. The magnitude of the unsteady force is very dependent on the clocking position.

Numerical and Experimental Investigation on the Flow Induced Oscillations of a Single-Blade Pump Impeller

2005 ◽  
Vol 128 (4) ◽  
pp. 783-793 ◽  
Author(s):  
F.-K. Benra
Keyword(s):  
Stokes Equations ◽  
Sewage Water ◽  
Hydrodynamic Forces ◽  
Time Dependent ◽  
Outer Side ◽  
Water Pump ◽  
Pump Rotor ◽  
Wide Range ◽  
Dependent Flow ◽  
Blade Pump

This contribution is addressed to the periodically unsteady flow forces of a single-blade sewage water pump, which affect the impeller and produce radial deflections of the pump shaft. The hydrodynamic excitation forces were calculated from the time dependent flow field, which was computed by numerical simulation of the three-dimensional, viscous, time-dependent flow in the pump. A commercial computer code was used to determine the time accurate Reynolds averaged Navier-Stokes equations. The transient radial flow forces at all time steps for a complete impeller revolution affect the rotor of the single-blade pump and stimulate it to strong oscillations. To determine the influence of the vibration stimulation forces on the dynamic behavior of the pump rotor, an investigation of the rotor’s structural dynamics was accomplished. A dynamic time analysis for the pump rotor provided the dynamic answer from the structural model of the rotor under the influence of the flow forces. The hydrodynamic forces, which were calculated before, were defined as external forces and applied as the load on the rotor. The resulting impeller deflections were calculated by a transient analysis of the pump rotor system using the commercial finite element method software PROMECHANICA. To verify the results obtained by standard numerical methods, the radial deflections of the impeller of a commercial sewage water pump, which has been investigated numerical in advance, were measured for the horizontal and for the vertical coordinate direction by proximity sensors. The measured data were compared to the computed amounts for a wide range of pump operation. The results show a good agreement for a strong part of an impeller revolution for all investigated operating points. The simultaneous measurement of vibration accelerations at the outer side of the pump casing showed the effects of the time-dependent flow, which produce hydrodynamic forces acting at the impeller of the pump and stimulating it to strong oscillations.

Microscale pressure fluctuations near waves being generated by the wind

1972 ◽  
Vol 54 (3) ◽  
pp. 427-448 ◽  
Author(s):  
J. A. Elliott
Keyword(s):  
Static Pressure ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Phase Speed ◽  
Sea Waves ◽  
Mean Wind Speed ◽  
The Mean ◽  
Active Wave ◽  
The Waves ◽  
Active Generation

Measurements of static pressure and wave height are used to describe the waveinduced pressure field above generating sea waves. A large hump in the pressure spectra is observed at the wave frequencies. The amplitude of this hump increases and the rate of its vertical decay decreases as the mean wind speed increases. The phase difference between the pressure and the waves during active generation is about 135°, pressure lagging the waves, and does not change vertically for measurements at heights greater than the wave crests. In the present data, active wave generation appears to occur only when the wind at a height of 5 metres is greater than or about equal to twice the phase speed of the waves.

МODERNIZATION TECHNOLOGY REPAIRING ACENTRIFUGAL WATER PUMP

2018 ◽  
pp. 48-51
Author(s):  
Sh.U. Yuldashev ◽  
D.T. Abdumuminova
Keyword(s):  
Production Process ◽  
Technological Process ◽  
Energy Efficient ◽  
Technical Support ◽  
Ultrasonic Processing ◽  
Water Pump ◽  
The Real ◽  
Technological Processes ◽  
Efficient Management ◽  
Pump Shaft

The article provides an overview of the principle of the pump D630-90, as well as methods for studying the real conditions of technical support to improve maintainability and optimize technological processes and systems. A technological process for the restoration of the shaft of a centrifugal water pump has been developed and an algorithm for managing it has been proposed, on the basis of which the system for energy-efficient management of the recovery area has been implemented. Also in the article some questions of use, metal-filled compound SK812, and also application of ultrasonic processing of a surface of a shaft of the centrifugal water pump of mark D630-90 are mentioned and considered. The developed technological process of pump shaft restoration showed that it is characterized by simplicity, it fits well into the production process of repair and can be widely used in repair shops.

scholarly journals Analysis of Performance of the Wind-Driven Pulverizing Aerator Based on Average Wind Speeds in the Conditions of Góreckie Lake

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2796
Author(s):  
Andrzej Osuch ◽  
Ewa Osuch ◽  
Stanisław Podsiadłowski ◽  
Piotr Rybacki
Keyword(s):  
Mathematical Model ◽  
Wind Speed ◽  
Water Pump ◽  
Average Wind Speed ◽  
Flow Rates ◽  
Wind Speeds ◽  
Average Wind ◽  
Flow Through ◽  
Analysis Of Performance ◽  
Research Period

In the introduction to this paper, the characteristics of Góreckie lake and the construction and operation of the wind-driven pulverizing aerator are presented. The purpose of this manuscript is to determine the efficiency of the pulverizing aerator unit in the windy conditions of Góreckie Lake. The efficiency of the pulverization aerator depends on the wind conditions at the lake. It was necessary to conduct thorough research to determine the efficiency of water flow through the pulverization segment (water pump). It was necessary to determine the rotational speed of the paddle wheel, which depended on the average wind speed. Throughout the research period, measurements of hourly average wind speed were carried out. It was possible to determine the efficiency of the machine by developing a dedicated mathematical model. The latest method was used in the research, consisting of determining the theoretical volumetric flow rates of water in the pulverizing aerator unit, based on average hourly wind speeds. Pulverization efficiency under the conditions of Góreckie Lake was determined based on 6600 average wind speeds for spring, summer and autumn, 2018. Based on the model, the theoretical efficiency of the machine was calculated, which, under the conditions of Góreckie Lake, amounted to 75,000 m3 per year.

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