scholarly journals Influence of impeller staggered arrangement on radial force and pressure fluctuation for a double-suction centrifugal pump

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878146 ◽  
Author(s):  
Yu Song ◽  
Zhiyi Yu ◽  
Guangtai Shi ◽  
Xiaobing Liu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Maximum Amplitude ◽  
Dominant Frequency ◽  
Radial Force ◽  
Pump Efficiency ◽  
Force Vector ◽  
Force Fluctuation ◽  
Staggered Arrangement ◽  
Maximum Improvement

Influence of impeller arrangement on performance, radial force, and pressure fluctuation for a double-suction centrifugal pump is investigated. In comparison of the original impeller with staggered angle α of 0°, the maximum improvement of pump efficiency is 2.19% for impeller with α of 30°, and the maximum improvement of pump head is 1.76% for impeller with α of 20°. The radial force vector on impeller is related to the staggered angle, and the phase angle of radial force vector is equal to the staggered angle. The staggered arrangement can effectively reduce the amplitude of radial force fluctuation. In comparison of case 0, the maximum amplitude of radial force fluctuation for case 30 reduces by 15.8%. The dominant frequencies of the radial force fluctuation for α = 0°, 10°, and 20° are fBP, while the dominant frequency for α = 30° is 2 fBP. An empirical formula is proposed to predict the radial fluctuation amplitude at specific staggered angle. For a point of the volute far from the exit volute, in comparison of case 0, the maximum amplitudes of pressure fluctuation for case 10, case 20, and case 30 are reduced by 13.1%, 49.8%, and 93.3%.

Unsteady Turbulent Simulation and Analysis of Pressure Fluctuation for High Temperature and High Pressure Centrifugal Pump

2011 ◽  
Author(s):  
Shuhong Liu ◽  
Yujun Sha ◽  
Yulin Wu ◽  
Baogang Wang
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Maximum Amplitude ◽  
Internal Flow ◽  
Dominant Frequency ◽  
Reference Points ◽  
Flow Passage ◽  
Key Factor

The pressure fluctuation in the internal flow passage of centrifugal pump is a key factor affecting the stability of the hydraulic system, especially working at conditions of high temperature and pressure. In this paper, RNG k–ε turbulent model is adopted to simulate the unsteady flow through the whole flow passage of centrifugal pump working at temperature T = 300 °C and high pressure P = 280 bar. The pressure fluctuation is calculated at the predefined reference points in the different planes. By analyzing the results, it is found that: 1) the rotor-stator interaction between impeller and diffuser is the main cause for pressure fluctuation; 2) the dominant frequency of pressure fluctuation in the flow passage of impeller is the diffuser passing frequency; 3) the dominant frequency at the points of casing wall is almost the same, and the maximum amplitude is relatively small.

Effect of Double-Volute Casing on Impeller Radial Force for a Large Double-Suction Centrifugal Pump

2015 ◽  
Author(s):  
Zichao Zhang ◽  
Fujun Wang ◽  
Zhifeng Yao ◽  
Ruofu Xiao
Keyword(s):  
Centrifugal Pump ◽  
Radial Force ◽  
Operating Conditions ◽  
Force Vector ◽  
Force Fluctuation ◽  
Impeller Outlet ◽  
Rib Structure ◽  
Operation Stability ◽  
Pump Shaft ◽  
The Difference

The operation stability of lager double-suction centrifugal pump is becoming an important issue. High radial force could result in fatigue failure of pump shaft and vibration of impeller. In order to find the effect of double-volute casing on impeller radial force, a double-suction centrifugal pump with two casing configurations is investigated by using CFD approach. The two casings have same geometry, the difference is that one is single-volute casing without dividing rib structure, another is double-volute casing with dividing rid structure. Results show that the dividing rib structure of double-volute casing could result in static pressure surrounding the impeller outlet is symmetry at every operating conditions, this is the reason why radial force of double-volute casing is lower than single-volute casing. The radial force vector diagrams for two casings are all hexagonal. However, radial force of double-volute casing is nearly equal at every operating condition, the centre of hexagon for double-volute casing is nearer to origin of coordinate, these results indicate radial force of double-volute casing is lower than single-volute casing. The rotating frequency and the blade passing frequency dominate the radial force fluctuation in single-volute casing, while both of them are almost not existed in double-volute casing. The results indicate that double-volute casing could significantly reduce radial force fluctuation in double-suction centrifugal pump.

scholarly journals Experimental Analysis on Pressure Fluctuation Characteristics of a Centrifugal Pump with Vaned-Diffuser

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 126
Author(s):  
Houlin Liu ◽  
Ruichao Xia ◽  
Kai Wang ◽  
Yucheng Jing ◽  
Xianghui He
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Dominant Frequency ◽  
Design Flow ◽  
Signal Source ◽  
Vaned Diffuser ◽  
Impeller Outlet ◽  
Variation Tendency ◽  
Design Flow Rate

Experimental measurements to analyze the pressure fluctuation performance of a centrifugal pump with a vaned-diffuser, which its specific speed is 190. Results indicate that the main cause of pressure fluctuation is the rotor-stator interference at the impeller outlet. The head of the pump with vaned-diffuser at the design flow rate is 15.03 m, and the efficiency of the pump with a vaned-diffuser at the design flow rate reaches 71.47%. Pressure fluctuation decreases gradually with increasing distance from the impeller outlet. Along with the increase of the flow rate, amplitude of pressure fluctuation decreases. The amplitude of pressure fluctuation at the measuring points near the diffusion section of the pump body is larger than other measuring points. The variation tendency of pressure fluctuation at P1–P10 is the same, while there are wide frequency bands with different frequencies. The dominant frequency of pressure fluctuation is the blade passing frequency. The rotor-stator interference between the impeller and the vaned-diffuser gives rise to the main signal source of pressure fluctuation.

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.

Study on Pressure Fluctuation and Fluctuation Reduction of a Micro Vortex Pump

2014 ◽  
Author(s):  
Feixi Zhang ◽  
Peng Wu ◽  
Dazhuan Wu
Keyword(s):  
Pressure Fluctuation ◽  
Vortex Motion ◽  
Maximum Amplitude ◽  
Dominant Frequency ◽  
Distribution Method ◽  
Noise And Vibration ◽  
Flow Noise ◽  
Static Pressure Distribution ◽  
Vortex Pump ◽  
Increasing Demand

With the increasing demand of small-flow and high-head pumps, vortex pump, which can be used in industry, agriculture, medical and aerospace etc., has become more and more popular as low specific pump. However, the pressure fluctuation of fluid in the vortex pump would cause flow noise and vibration which may result in damage to the equipment. Clearly, it is important to reduce the fluctuation causing by fluid flow as much as possible. This study examined and discussed the law of pressure fluctuation in a micro vortex pump by the method of numerical simulation. In addition, a random distribution method was applied to design two new impellers with different blade spacing. Moreover, the influence on pressure fluctuation of different blade positions was predicted by theoretical analysis and CFD analysis. The results show that the blade passing frequency is dominative in the pressure fluctuation. Although the average static pressure distribution on the circumference of the micro vortex pump increased gradually along inlet to outlet, the pressure pulse amplitudes were fluctuant and the maximum amplitude area was close to the stripper. Affected by the vortex motion in the pump, there were clutters in the spectrum from inlet to outlet even for the vortex pump with uniform circumferential blade spacing. The study also indicated that uneven circumferential spacing would yield additional frequency in the spectrum compared with even one and reduce the magnitude of the dominant frequency without decreasing the performance of the pump sharply. Based on the consequence, this paper proves the feasibility of applying uneven blade spacing to reduce pressure fluctuation in a vortex pump. And it could be meaningful for the noise and vibration reduction as well as development of vortex pumps.

The Influence of Vaned Diffuser Outlet Diameters on Operating Performance of a Single-Stage Centrifugal Pump

2018 ◽  
Author(s):  
Xiangyuan Zhu ◽  
Fen Lai ◽  
Liping Zhu ◽  
Guojun Li
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Numerical Approach ◽  
Radial Force ◽  
Hydrodynamic Performance ◽  
Stable Operation ◽  
Vaned Diffuser

To enhance the efficiency and stable operation, the unsteady pressure fluctuations in a centrifugal pump and the radial force on an impeller are investigated for three different vaned diffuser outlet diameters. The steady-state hydrodynamic performance of the centrifugal pump with three different vaned diffuser outlet diameters was experimentally measured. Numerical simulations were used to obtain the hydrodynamic performance of the experimental centrifugal pump based on the Reynolds-averaged Navier-Stokes (RANS) and turbulence models. The numerical results of the hydrodynamic performance were in agreement with the experimental data. The accuracy of the utilized numerical approach was demonstrated. The unsteady flow characteristics of the centrifugal pump were numerically studied. With increasing diffuser vane outlet diameter, the flow field within the volute became more non-uniform, and the pressure fluctuation was more drastic. Moreover, because of the influence of the non-uniform flow field and the pressure fluctuation, the radial force on the impeller increased.

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.

Numerical simulation of unsteady cavitation flow in a centrifugal pump at off-design conditions

2013 ◽  
Vol 228 (11) ◽  
pp. 1994-2006 ◽  
Author(s):  
Tan Lei ◽  
Zhu Bao Shan ◽  
Cao Shu Liang ◽  
Wang Yu Chuan ◽  
Wang Bin Bin
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Partial Discharge ◽  
Maximum Amplitude ◽  
Maximum Pressure ◽  
Pressure Amplitude ◽  
Cavitation Flow ◽  
Frequency Spectra ◽  
Large Discharge

Unsteady cavitation flows in a centrifugal pump operating under off-design conditions are investigated by using a numerical framework combining the re-normalization group k–ɛ turbulence model and the transport equation-based cavitation model. The reliability and accuracy of the numerical model are demonstrated by the satisfactory agreement between the experimental and numerical values of the pump performance. Under partial discharge, the frequency spectra of the pressure fluctuation at the impeller inlet become more complex as the pump inlet pressure decreases. The maximum amplitude of pressure fluctuation at the blade leading edge for cavitation flow is 2.54 times larger than that for non-cavitation flow because of the violent disturbances caused by cavitation shedding and explosion. Under large discharge, the magnification on the maximum pressure amplitude is 1.6. This finding indicates that cavitation has less influence on pressure fluctuations in the impeller under large discharge than under partial discharge. This numerical simulation demonstrates the evolution of cavitation structure inside the impeller.

scholarly journals Experimental Investigation on Influence of Relative Positions Between Diffuser and Volute on Pressure Fluctuation at the Outlet of a Centrifugal Pump

2016 ◽  
Author(s):  
Wenjie Wang ◽  
Shouqi Yuan ◽  
Ji Pei ◽  
Giorgio Pavesi ◽  
Yandong Gu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Load Condition ◽  
Dominant Frequency ◽  
Azimuthal Position ◽  
Open Test ◽  
Spectrum Density ◽  
Fluctuation Amplitude ◽  
Large Flow

To investigate the influence of relative positions between a radial diffuser and an annular volute on the unsteady pressure at the centrifugal pump outlet, experiment tests were carried out with five positions between the diffuser and volute in an open test rig. Statistical and frequency spectrum analyses were carried out to obtain the pressure fluctuation amplitude range and the frequency domain respectively. The results showed that the relative position has greater influence on the pressure at large flow rate than at part load condition. The dominant frequency and the Power Spectrum Density (PSD) values are affected by diffuser azimuthal position and the harmonic frequencies are determined by number of blades and vanes. The investigation can give a reference to optimize the relative angle between diffuser and volute to reduce the pressure fluctuations.

Influence of Geometry of Inlet Guide Vanes on Pressure Fluctuations of a Centrifugal Pump

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Ming Liu ◽  
Lei Tan ◽  
Shuliang Cao
Keyword(s):  
Centrifugal Pump ◽  
Turbulence Model ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Maximum Amplitude ◽  
Dominant Frequency ◽  
Centrifugal Pumps ◽  
Maximum Increase ◽  
Guide Vanes ◽  
Inlet Guide Vanes

Prewhirl regulation by inlet guide vanes (IGVs) has been proven as an effective method for operation regulation of centrifugal pumps. By contrast, the influence of the geometry of IGVs on operation stability of centrifugal pump remains unknown. The pressure fluctuations and flow patterns in a centrifugal pump without and with two-dimensional (2D) or three-dimensional (3D) IGVs are investigated numerically at 1.0Qd, 0.6Qd, and 1.2Qd. Renormalization group (RNG) k–ε turbulence model is used as turbulence model, and fast Fourier transform (FFT) method is used to analyze the pressure fluctuations. The dominant frequency of pressure fluctuations in impellers is either the rotational frequency fi or twice thereof for pumps without and with IGVs at three flow rates, while the dominant frequency is constantly the blade passing frequency in volute. For 1.0Qd, the comparison of pumps without IGVs indicates that the maximum amplitude of pressure fluctuations at fi in pumps with 2D IGVs is decreased by an average of 22.2%, and the amplitude is decreased by an average of 44.9% in pumps with 3D IGVs. The IGVs mainly influence the pressure fluctuations at fi but indicate minimal influence at 2fi. For 0.6Qd, the comparison of pumps without IGVs denotes that the maximum amplitudes of pressure fluctuations at fi in pumps with 2D or 3D IGVs both increase; the maximum increase is 2.01%. For 1.2Qd, the comparison of pumps without IGVs indicates that the maximum amplitudes of pressure fluctuations at fi in pumps with 2D or 3D IGVs both decrease; the maximum decline is 15.9%.

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