An Experimental Investigation of Radial Thrust in Centrifugal Pumps

1960 ◽  
Vol 82 (2) ◽  
pp. 120-125 ◽  
Author(s):  
A. Agostinelli ◽  
D. Nobles ◽  
C. R. Mockridge
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Pump ◽  
Graphical Form ◽  
Strain Gages ◽  
Centrifugal Pumps ◽  
Speed Range ◽  
Radial Forces ◽  
Specific Speed ◽  
Radial Thrust

An experimental investigation has been conducted to determine the magnitudes and directions of the unbalanced radial forces on centrifugal pump impellers. The work covers single volutes for a wide specific speed range, double volutes, concentric casings, and modifications of the concentric casing. The results are presented in graphical form and are discussed. A method, making use of strain gages, was devised for determining the magnitudes and directions of the resultant radial forces and is described.

Radial Force on the Impeller of Centrifugal Pumps With Volute, Semivolute, and Fully Concentric Casings

1965 ◽  
Vol 87 (3) ◽  
pp. 319-322 ◽  
Author(s):  
H. Joseph Biheller
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Pump ◽  
Radial Force ◽  
Operating Speed ◽  
Centrifugal Pumps ◽  
Operating Range ◽  
Aspect Ratios ◽  
Radial Forces

An experimental investigation of the magnitude and direction of the unbalanced radial force on centrifugal pump impellers was made. Pumps with single volute, semiconcentric and fully concentric casings of several specific speeds, collector aspect ratios, and with both closed and semiclosed impellers were tested over the full operating range. An equation enabling prediction of expected radial forces based only on pump geometry, operating speed, and capacity (expressed as fraction of capacity at best efficiency) is presented.

Performance and Internal Flow Characteristics of a Very Low Specific Speed Centrifugal Pump

2005 ◽  
Vol 128 (2) ◽  
pp. 341-349 ◽  
Author(s):  
Young-Do Choi ◽  
Junichi Kurokawa ◽  
Jun Matsui
Keyword(s):  
Centrifugal Pump ◽  
Reverse Flow ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Positive Displacement ◽  
Speed Range ◽  
Low Specific Speed ◽  
Specific Speed

In very low specific speed range (ns<0.25), the efficiency of the centrifugal pump designed by the conventional method becomes remarkably low. Therefore, positive-displacement pumps have been widely used for long. However, the positive-displacement pumps remain associated with problems such as noise and vibration and they require high manufacturing precision. Since the recently used centrifugal pumps are becoming higher in rotational speed and smaller in size, there appear to be many expectations to develop a new centrifugal pump with high performance in the very low specific speed range. The purpose of this study is to investigate the internal flow characteristics and its influence on the performance of a very low specific speed centrifugal pump. The results show that large reverse flow at the semi-open impeller outlet decreases absolute tangential velocity considerably which in turn decreases the pumping head.

scholarly journals Optimal Design of Slit Impeller for Low Specific Speed Centrifugal Pump Based on Orthogonal Test

2021 ◽  
Vol 9 (2) ◽  
pp. 121
Author(s):  
Yang Yang ◽  
Ling Zhou ◽  
Hongtao Zhou ◽  
Wanning Lv ◽  
Jian Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Large Scale ◽  
Internal Flow ◽  
Orthogonal Test ◽  
Centrifugal Pumps ◽  
Initial Model ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Four Levels

Marine centrifugal pumps are mostly used on board ship, for transferring liquid from one point to another. Based on the combination of orthogonal testing and numerical simulation, this paper optimizes the structure of a drainage trough for a typical low-specific speed centrifugal pump, determines the priority of the various geometric factors of the drainage trough on the pump performance, and obtains the optimal impeller drainage trough scheme. The influence of drainage tank structure on the internal flow of a low-specific speed centrifugal pump is also analyzed. First, based on the experimental validation of the initial model, it is determined that the numerical simulation method used in this paper is highly accurate in predicting the performance of low-specific speed centrifugal pumps. Secondly, based on the three factors and four levels of the impeller drainage trough in the orthogonal test, the orthogonal test plan is determined and the orthogonal test results are analyzed. This work found that slit diameter and slit width have a large impact on the performance of low-specific speed centrifugal pumps, while long and short vane lap lengths have less impact. Finally, we compared the internal flow distribution between the initial model and the optimized model, and found that the slit structure could effectively reduce the pressure difference between the suction side and the pressure side of the blade. By weakening the large-scale vortex in the flow path and reducing the hydraulic losses, the drainage trough impellers obtained based on orthogonal tests can significantly improve the hydraulic efficiency of low-specific speed centrifugal pumps.

scholarly journals Numerical Simulation of 3D Solid-Liquid Turbulent Flow in a Low Specific Speed Centrifugal Pump: Flow Field Analysis

2014 ◽  
Vol 6 ◽  
pp. 814108 ◽  
Author(s):  
Baocheng Shi ◽  
Jinjia Wei
Keyword(s):  
Turbulent Flow ◽  
Centrifugal Pump ◽  
Centrifugal Pumps ◽  
Numerical Convergence ◽  
Phase Calculation ◽  
Low Specific Speed ◽  
Specific Speed ◽  
3D Solid ◽  
Solid Liquid ◽  
Numeral Simulation

For numerically simulating 3D solid-liquid turbulent flow in low specific speed centrifugal pumps, the iteration convergence problem caused by complex internal structure and high rotational speed of pump is always a problem for numeral simulation researchers. To solve this problem, the combination of three measures of dynamic underrelaxation factor adjustment, step method, and rotational velocity control means according to residual curves trends of operating parameters was used to improve the numerical convergence. Numeral simulation of 3D turbulent flow in a low specific speed solid-liquid centrifugal pump was performed, and the results showed that the improved solution strategy is greatly helpful to the numerical convergence. Moreover, the 3D turbulent flow fields in pumps have been simulated for the bottom ash-particles with the volume fraction of 10%, 20%, and 30% at the same particle diameter of 0.1 mm. The two-phase calculation results are compared with those of single-phase clean water flow. The calculated results gave the main region of the abrasion of the impeller and volute casing and improve the hydraulic design of the impeller in order to decrease the abrasion and increase the service life of the pump.

Hydrodynamic Design of the Volute of a Centrifugal Pump Using CFD

2011 ◽  
Author(s):  
Rouhollah Torabi ◽  
S. Ahmad Nourbakhsh
Keyword(s):  
Viscous Flow ◽  
Centrifugal Pump ◽  
Static Pressure ◽  
Design Method ◽  
Radial Force ◽  
Inverse Design ◽  
Radial Forces ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Inverse Design Method

The objective of this paper is to develop the shape of an existing volute so that the radial forces in off-design condition become minimum. For this purpose 3-D inverse design method based on the 3-D viscous flow calculations was applied to re-design the geometry of the volute of a low specific speed pump. Various aspects of the geometry change independently to achieve the best one which produces less radial force in off design conditions. Measurements included time-averaged values of velocity and static pressure at a large number of locations in the volute.

The effect of wear ring clearance on flow field in the impeller sidewall gap and efficiency of a low specific speed centrifugal pump

2017 ◽  
Vol 232 (17) ◽  
pp. 3062-3073 ◽  
Author(s):  
M DaqiqShirazi ◽  
R Torabi ◽  
A Riasi ◽  
SA Nourbakhsh
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Volumetric Efficiency ◽  
Centrifugal Pumps ◽  
Disk Friction ◽  
Low Specific Speed ◽  
Overall Efficiency ◽  
Specific Speed

In this paper, the flow in the impeller sidewall gap of a low specific speed centrifugal pump is analyzed to study the effect of wear ring clearance and the resultant through-flow on flow field in this cavity and investigate the overall efficiency of the pump. Centrifugal pumps are commonly subject to a reduction in the flow rate and volumetric efficiency due to abrasive liquids or working conditions, since the wear rings are progressively worn, the internal leakage flow is increased. In the new operating point, the overall efficiency of the pump cannot be predicted simply by using the pump characteristic curves. The flow field is simulated with the use of computational fluid dynamics and the three-dimensional full Navier–Stokes equations are solved using CFX software. In order to verify the numerical simulations, static pressure field in volute casing and pump performance curves are compared with the experimental measurements. The results show that, for the pump with minimum wear ring clearance, the disk friction efficiency is the strongest factor that impairs the overall efficiency. Therefore, when the ring clearance is enlarged more than three times, although volumetric efficiency decreases effectively but the reduction in overall efficiency is remarkably smaller due to improvement in the disk friction losses.

Numerical Investigation of Viscous Flow in Three Centrifugal Pumps

2012 ◽  
Author(s):  
Carlos Luis Moreno ◽  
Alejandro Fuenmayor ◽  
Gilberto Núñez ◽  
Jesús De Andrade ◽  
Ricardo Noguera ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Viscous Flow ◽  
Centrifugal Pump ◽  
Fluid Viscosity ◽  
Centrifugal Pumps ◽  
Impeller Blade ◽  
Pump Turbine ◽  
Viscous Liquids ◽  
Pump Performance ◽  
Radial Forces

Centrifugal pump performance is affected when pumping viscous liquids, requiring a larger power input than the same pump handling water. In applications of chemical, civil, environmental, and mechanical engineering that involve centrifugal pumps, it is a challenge to accurately estimate and even more of a challenge to improve their performance when handling viscous liquids. When accurate performance data is needed, difficult experiments must be conducted with the operating viscous flow. The extension of the applicability of numerical techniques for solving fluid dynamics (CFD) permits the consideration of these tools as a definite possibility for predicting the performance of centrifugal pumps with viscous flows. The purpose of this study is to perform a 3D-CFD steady-state simulation of three different configurations of centrifugal pumps. The first is an impeller-diffuser pump (ns = 19) taken from an ESP model. The second is a Francis Pump-Turbine (ns = 28). Finally, the third configuration possesses an impeller and volute (ns = 32). The objective is to characterize and evaluate their performances with four different fluids from 1 to 420 cSt. These are: water at 25°C, SAE10 and SAE30 oils, and Fuel Oil Medium (FOM). For water flow conditions, the numerical results were compared with experimental data, and found to be consistent with global performance parameters. With regard to the higher viscosity fluids, the CFD calculation was compared with those obtained through the standard empirical method (ANSI/HI9.6.7). This resulted in good agreement between the performance results. The commercial software ANSYS-CFX was used for the CFD calculations. The resulting pump performance curve (head, hydraulic efficiency and power output) is consistent with that expected by theory. In general, as the viscosity of fluids increases, the hydraulic energy losses increase. Of the three pumps, slip factor for SAE30 oil was larger for all volumetric flows since it features the best guidance of the flow in the impeller blade passage. For the ns32 pump and the pump-turbine ns28, the volute losses rose from water to FOM, just like the impeller hydraulic losses. For these two turbo machines, the impeller losses were larger than volute losses. For the pumps with volute, the effects of fluid viscosity on the radial forces were evaluated. It was found that the radial forces decrease when the viscosity increases. This paper attempts to contribute to a better understanding of fluid dynamics within centrifugal pump impellers handling viscous fluids, and intends to shed more light on the approaches that performance prediction models should follow in the future.

scholarly journals Comparison of energy parameters of a centrifugal pump with a multi-piped impeller in cooperation either with an annular channel and a spiral channel

2018 ◽  
Vol 8 (1) ◽  
pp. 513-522 ◽  
Author(s):  
Bartłomiej Chomiuk ◽  
Janusz Skrzypacz
Keyword(s):  
Centrifugal Pump ◽  
Annular Channel ◽  
Operating Parameters ◽  
Centrifugal Pumps ◽  
Impeller Outlet ◽  
Flow Geometry ◽  
Quantitative Verification ◽  
Flow Through ◽  
Low Specific Speed ◽  
Specific Speed

Abstract The article presents results of numerical analyzes, which raise a subject of influence of the cooperation the multi-piped impeller with a rationalized flow geometry of annular casing and volute casing for liquid flow through centrifugal pump and their operating parameters in the extremely low specific speed nq<10. The multi-piped impeller (patented by authors) is a major alternative to classic vane impellers. The stator type is responsible for the conversion of the kinetic energy of the liquid by the impeller outlet into potential energy, which determines the overall efficiency of the pump. Also, the article presents qualitative and quantitative verification of results obtained by computer modeling and an attempt to estimate their accuracy. The article focuses mainly on the comparison of the performance parameters of the pump with a multi-piped impeller in cooperation with two stator types with a rationalized flow geometry. Both outlet elements were tested in various configurations of constructional features. The complexity of the construction of the stator can significantly affect the manufacturing costs of pump unit. Knowledge concerning construction of hydraulic elements of centrifugal pumps working in the range of parameters corresponding specific speed (nq<10) is insufficient. As shown in the paper, the annular type casing model pump cooperating with a multi-piped impeller, designed in accordance with literature, reached far poorer operating parameters than the rational annular construction in a configuration with the same impeller.

scholarly journals Experimental and Numerical Investigation of Radial Forces Acting on Centrifugal Pump Impeller

2014 ◽  
Vol 61 (3) ◽  
pp. 445-454 ◽  
Author(s):  
Krzysztof Karaskiewicz ◽  
Marek Szlaga
Keyword(s):  
Centrifugal Pump ◽  
Rectangular Cross Section ◽  
Radial Force ◽  
Axial Thrust ◽  
Pump Impeller ◽  
Ansys Fluent ◽  
Commercial Code ◽  
Radial Forces ◽  
Radial Thrust ◽  
Centrifugal Pump Impeller

Abstract The paper presents the results of measurements and predictions of radial thrust in centrifugal pump with specific speed ns = 26. In the pump tested, a volute with rectangular cross-section was used. The tests were carried out for several rotational speeds, including speeds above and below the nominal one. Commercial code ANSYS Fluent was used for the calculations. Apart from the predictions of the radial force, the calculations of axial thrust were also conducted, and correlation between thrust and the radial force was found. In the range of the measured rotational speeds, similarity of radial forces was checked.

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