Effect of Relative Impeller-to-Volute Position on Hydraulic Efficiency and Static Radial Force Distribution in a Circular Volute Centrifugal Pump

2000 ◽  
Vol 122 (3) ◽  
pp. 598-605 ◽  
Author(s):  
Daniel O. Baun ◽  
Lutz Ko¨stner ◽  
Ronald D. Flack
Keyword(s):  
Centrifugal Pump ◽  
Relative Position ◽  
Hydraulic Performance ◽  
Radial Force ◽  
Design Flow ◽  
Flow Coefficient ◽  
Geometric Center ◽  
Hydraulic Force ◽  
Radial Thrust ◽  
Force Characteristics

The hydraulic performance and radial hydraulic force characteristics of a circular volute centrifugal pump are strongly affected by the impeller to volute relative position. For a typical design configuration the geometric center of the impeller will be coincident with the volute geometric center. However, assembling a circular volute pump with the impeller center eccentric from the volute center can radically alter both the hydraulic performance and the radial hydraulic force characteristics. In particular, at the design flow coefficient an optimum impeller to volute relative position exists where the efficiency is maximized and the resultant radial force is minimized. At the optimal relative position a 5 percent and a 3.5 percent increase in the efficiency was realized compared to the centered positions for the circular and spiral volutes, respectively. In addition the nondimensional resultant radial force at the design flow coefficient was reduced from 0.045 at the centered position to 0.005 at the optimal position for the circular casing. This value of radial thrust is similar in magnitude to the radial thrust for the spiral volute operating at the design flow coefficient. By assembling a circular volute pump with the appropriate relative impeller to volute position the design simplicity of a circular volute can be utilized without compromising pump hydraulic performance or radial force characteristics as compared to a typical spiral volute. [S0098-2202(00)02303-8]

Hydraulic Design of Inlet Guide Vane and its Full Flow Passage Numerical Simulation on Centrifugal Pump

2014 ◽  
Author(s):  
Hucan Hou ◽  
Yongxue Zhang ◽  
Zhenlin Li ◽  
Xin Zhou ◽  
Zizhe Wang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Guide Vane ◽  
Hydraulic Performance ◽  
Design Flow ◽  
Inlet Guide Vane ◽  
Hydraulic Efficiency ◽  
Flow Passage ◽  
Setting Angle ◽  
Hydraulic Design

In order to effectively improve hydraulic performance of centrifugal pump on off-conditions, the hydraulic design of inlet guide vane (IGV) was completed by adopting two dimensional theory in-house code based on one kind of IS series of centrifugal pump, which can achieve pre-whirl regulation of centrifugal pump. During design process the trailing edge of vane is assumed as equal velocity moment condition, and the distribution of vane setting angle along meridional streamline is also given as a quartic function firstly, the camber line is then drawn by point-by-point integration method and thickened at both sides along circumferential direction. With local vortex dynamics diagnosis theory, the optimal improvement of vane space shape can be finished by adjusting the design parameters of vane setting angle distribution coefficient ap. The full flow passage numerical simulations of centrifugal pump with IGV device are completed to analyze the influence of pre-whirl regulation on hydraulic performance of centrifugal pump under various pre-whirl angles. The results show that the pre-whirl regulation can improve the hydraulic performance of centrifugal pump on off-conditions. Under the positive pre-whirl regulation conditions, the best efficient point shift to small flow rate zone, and under the negative pre-whirl regulation conditions it moves to large flow rate zone. Compared with the pump without IGV device at the same flow rate condition of 0.8Q (Q the design flow rate), the hydraulic efficiency of centrifugal pump with IGV device improves obviously and reaches up to 1.43%. Meanwhile compared with that installed with the straight vanes designed based on the traditional theory, the inner flow field of centrifugal pump with the designed vanes improves and the overall hydraulic efficiency of centrifugal pump is somewhat increased.

Clocking effect in a centrifugal pump with a vaned diffuser

2020 ◽  
Vol 34 (26) ◽  
pp. 2050286
Author(s):  
Fen Lai ◽  
Xiangyuan Zhu ◽  
Yongqiang Duan ◽  
Guojun Li
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Loss ◽  
Total Pressure ◽  
Radial Force ◽  
Design Flow ◽  
Total Pressure Loss ◽  
Inlet Section ◽  
Centrifugal Pumps ◽  
Installation Angle

The performance and service life of centrifugal pumps can be influenced by the clocking effect. In this study, 3D numerical calculations based on the k-omega shear stress transport model are conducted to investigate the clocking effect in a centrifugal pump. Time-averaged behavior and transient behavior are analyzed. Results show that the optimum diffuser installation angle in the centrifugal pump is [Formula: see text] due to the minimum total pressure loss and radial force acting on the impeller. Total pressure loss, particularly in the volute, is considerably influenced by the clocking effect. The difference in total pressure loss in the volute at different clocking positions is 2.75 m under the design flow rate. The large total pressure loss in the volute is primarily caused by the large total pressure gradient within the vicinity of the volute tongue. The radial force acting on the impeller is also considerably affected by the clocking effect. When the diffuser installation angle is [Formula: see text], flow rate fluctuations in the volute and impeller passage are minimal, and flow rate distribution in the diffuser passage is more uniform than those in other diffuser installation angles. Moreover, static pressure fluctuations in the impeller midsection and the diffuser inlet section are at the minimum value. These phenomena explain the minimum radial force acting on the impeller. The findings of this study can provide a useful reference for the design of centrifugal pumps.

scholarly journals Efficiency improvement and evaluation of a centrifugal pump with vaned diffuser

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401982590 ◽  
Author(s):  
Kai Wang ◽  
Yu-cheng Jing ◽  
Xiang-hui He ◽  
Hou-lin Liu
Keyword(s):  
Centrifugal Pump ◽  
Axial Force ◽  
Flow Rate ◽  
Pressure Pulsation ◽  
Energy Performance ◽  
Radial Force ◽  
Design Flow ◽  
Vaned Diffuser ◽  
Original Scheme ◽  
Design Flow Rate

In order to enhance the efficiency of centrifugal pump, the structure of a centrifugal pump with vaned diffuser, whose specific speed is 190, was numerically improved by trimming back-blades of impeller and smoothing sharp corner in annular chamber. The energy performance, the internal flow field, the axial force, the radial force, and the pressure pulsation of the pump were analyzed. Results show that efficiency of the improving scheme 1 under the design flow rate is 77.47%, which can balance 69.82% of the axial force, while efficiency of the improving scheme 2 under the design flow rate is the maximum, which could still balance 62.74% of the axial force. The pressure pulsations of the improving scheme 2 at the typical monitoring points are less than that of the improving scheme 1 and the original scheme. The difference of the radial force peak between the improving scheme 1 and the improving scheme 2 is very small. The vector distributions of the radial force of the improving scheme 1 and the improving scheme 2 are more uniform than that of the original scheme. Considering the efficiency, pressure pulsation, and axial force, experiment measurements on the improving scheme 2 were carried out to verify the effectiveness of the improvement result. Results of energy performance experiment show that efficiency of the improving scheme 2 under the design flow rate is 76.48%, which is 5.26 percentage points higher than that of the original scheme.

Radial Thrust of Single-Blade Centrifugal Pump

2011 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Junichiro Fukutomi ◽  
Ryota Fujiwara
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Design Flow ◽  
Centrifugal Impeller ◽  
Cfd Analysis ◽  
Shearing Stress ◽  
Pump Operation ◽  
Grand Total ◽  
Conservation Of Momentum ◽  
Radial Thrust

A single-blade centrifugal pump is widely used as a sewage pump. However, a single-blade is acted on by a large radial thrust during the pump operation because of the geometrical axial asymmetry of the impeller. Therefore to secure the pump reliability, it is necessary to grasp the radial thrust quantitatively and elucidate a behavior and a generation mechanism. This study investigated the radial thrust acting on a single-blade centrifugal impeller by an experiment and a CFD analysis, and the results clearly indicated the following facts. The fluctuating component of the radial thrust increased as the flow rate changed from the design flow rate to a partial or excessive flow rate. Furthermore, the radial thrust was modeled by a combination of three components, inertia, momentum and pressure components by applying unsteady conservation of momentum to this impeller. The grand total of these components was in agreement with the radial thrust calculated by integrating the pressure and the shearing stress on the impeller surface. In addition the behavior of each component was shown and the effects of those components that gave to the radial thrust were clarified. The pressure component had the greatest effect on a time-averaged value and a fluctuating component of the radial thrust. The time-averaged value of the inertia component was approximately 0 even if the flow rate changed. But its fluctuating component had a magnitude nearly comparable to the pressure component at a partial flow rate and slightly decreased with increase of the flow rate.

Pressure Fluctuation of the Low Specific Speed Centrifugal Pump

2012 ◽  
Vol 152-154 ◽  
pp. 935-939 ◽  
Author(s):  
Qiang Fu ◽  
Shou Qi Yuan ◽  
Rong Sheng Zhu
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
High Frequency ◽  
Pressure Fluctuations ◽  
Radial Force ◽  
Design Flow ◽  
Rate Condition ◽  
Low Specific Speed ◽  
Specific Speed

In order to study the rules of pressure fluctuation and the radial force under different positions in a centrifugal pump with low specific speed, and to find the relationship between each other, the three-dimensional ,unsteady Reynolds-averaged Navier-stokes equations with shear stress transport turbulent models were solved. The pressure fluctuation was obtained. The results showed that the pressure fluctuations were visible. The pressure fluctuations in the volute were relatively low at the design flow rate condition. The blade passing frequency dominates the pressure fluctuations, high frequency contents were found on the outlet of impeller but no high frequency information occured in casing. The radial force on the impeller was unsteady especially at the small flow rate.

Effect of vaned diffuser clocking position on hydraulic performance and pressure pulsation of centrifugal pump

2020 ◽  
pp. 095765092096724
Author(s):  
Hongyu Guan ◽  
Wei Jiang ◽  
Yuchuan Wang ◽  
Gaoyang Hou ◽  
Xiangyuan Zhu ◽  
...  
Keyword(s):  
Energy Loss ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Guide Vane ◽  
Hydraulic Performance ◽  
Design Flow ◽  
Maximum Difference ◽  
Centrifugal Pumps ◽  
Vaned Diffuser ◽  
Diffuser Flow

The clocking position of the vaned diffuser, the circumferential position of the vaned diffuser relative to the volute, has a certain effect on the performance of the centrifugal pump. Therefore, this paper studies the guide vane centrifugal pump from the aspects of pressure pulsation, hydraulic performance, and energy loss. The maximum difference in efficiency is 3.4% under the design flow rate, and the maximum difference in the head coefficient is 4.7%. The hydraulic performance and pressure pulsation present different trends with the increase of the vaned diffuser clock angle. When the hydraulic performance and pressure pulsation are relatively good, the circumferential distance between the tongue and the upstream vaned diffuser blade is 3/4 of the diffuser flow path. In addition, the recommended vaned diffuser installation location may also be suitable for centrifugal pumps of similar construction. The energy loss was visualized using the theory of entropy production. The distributions of energy loss and flow field indicate that the energy loss of impeller and vaned diffuser changes little. The change of the vortex in the tongue and outlet area will cause a significant change in the energy loss of the volute, which is the main reason that the hydraulic performance of the centrifugal pump is affected by the clocking position of the vaned diffuser.

scholarly journals Effects of impeller trim on performance of two-stage self-priming centrifugal pump

2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769249 ◽  
Author(s):  
Kai Wang ◽  
Zixu Zhang ◽  
Linglin Jiang ◽  
Houlin Liu ◽  
Yu Li
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Guide Vane ◽  
Radial Force ◽  
Design Flow ◽  
Two Stage ◽  
Rate Condition ◽  
Application Range ◽  
Save Energy

In order to save energy by broadening its application range, the influence of impeller trim on the performance of a two-stage self-priming centrifugal pump was numerically studied. The hydraulic performance experiments and self-priming experiments were carried out. And the unsteady performance of pressure fluctuation and radial force in the pump was analyzed. The results show that with the increase in impeller trim quantity, the best efficiency point of the pump would move to the small flow rate condition. Under the design flow rate, when both the two stages of the impeller were trimmed by 6%, head of the pump was reduced by 13%, efficiency of the pump was as well decreased by 1.69 percentage points, and self-priming time was increased by 1.7%. Thus, impeller trim can be used to meet the operating requirements in the head range of 94–107 m. With the increase in impellers trim quantity, the pressure fluctuation in the positive channel of the radial guide vane and the volute was smaller, while the radial force on the wall of radial guide vane and volute was also smaller.

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.

Analysis of the Pressure Pulsation and Vibration in a Low-Specific-Speed Centrifugal Pump

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Baoling Cui ◽  
Yingbin Zhang ◽  
Yakun Huang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Vortex Core ◽  
Pressure Pulsation ◽  
Radial Force ◽  
Design Flow ◽  
Low Flow ◽  
Pressure Pulsations ◽  
Low Specific Speed ◽  
Specific Speed

Abstract Unsteady pressure pulsation and fluid force induced by flow instabilities in the centrifugal pump is an important cause of vibration, which is detrimental to the safe operation of the pump. In this study, we numerically investigated the pressure pulsation and radial force in a low-specific-speed centrifugal pump by using the detached-eddy simulation method. We also performed a vibration displacement experiment on the shaft of the centrifugal pump. The vortex identification method was introduced to clarify the internal correlation between unsteady flow structures with pressure pulsations. The results showed that the pressure pulsations at the impeller outlet were closely associated with the periodic vortex shedding from the blade pressure surface. The rotor–stator interaction between a relatively big trailing vortex core and volute tongue generated larger pressure pulsation and radial force in the pump at a low flow rate. Under a large flow rate, the trailing vortex core was easily broken and dispersed, and this resulted in smaller pressure pulsation and radial force compared with that at a low flow rate. Under the design flow rate, the pressure pulsation intensity and the radial force in the impeller were smaller than that under the off-design flow rate. Compared with the spectra between the radial force on the impeller and radial displacement on the shaft, they both presented higher amplitude at the shaft frequency. The vibration of the pump shaft was closely related to the radial force on the impeller.

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