Effects of Splitter Vanes on the Performance and Pressure Pulsation in a Centrifugal Pump

2019 ◽  
Author(s):  
Chao Li ◽  
Bo Gao ◽  
Ning Zhang ◽  
Dan Ni
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Pulsation ◽  
Suction Side ◽  
Wake Flow ◽  
Field Analysis ◽  
Centrifugal Impeller ◽  
Optimized Design ◽  
Rate Condition ◽  
Pump Head

Abstract Two types of arrangement of splitter vanes at the outlet of a centrifugal impeller is proposed in this paper, that is, staggered vanes and splitter vanes. By means of CFD, the effects of different vanes arrangement schemes on the performance and pressure fluctuation characteristics of the centrifugal pump are compared. The influence mechanism of different schemes is explored based on the fluid flow field analysis. The results show that, compared with ordinary impellers, when the short vanes are 10 degree offset to the suction side of the main vanes, staggered vanes impellers cause the pump head and efficiency to decrease, while the amplitude of pressure pulsation at blade passing frequency (BPF) is reduced by 28% compared with that of the ordinary impeller under the design condition. In the splitter vanes scheme, the pump head and efficiency increased, however the efficiency increased more significantly under the large flow rate condition. The amplitude of pressure fluctuation at BPF is decreased by 14% compared with that of the ordinary impeller under the design condition. The existence of short vanes in both schemes changes the wake flow structure downstream the impeller vanes and tends to weaken the pressure pulsation induced by the rotor-stator interaction (RSI) phenomenon. The results can provide a reference for optimized design of the low vibration and less noisy pumps.

Study on the Reduction of Pressure Fluctuation for a Double-Suction Centrifugal Pump With Staggered Blades

2018 ◽  
Author(s):  
Qian-qian Li ◽  
Da-zhuan Wu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Low Noise ◽  
Living Environment ◽  
Centrifugal Impeller ◽  
Fluctuation Analysis ◽  
Centrifugal Pumps ◽  
Vibration Performance

Due to the distinctive characteristic of massive flow rates, double-suction centrifugal pump has been extensively applied in lots of perspectives, such as drainage, irrigation, transportation projects and other hydraulic engineering realms. Nevertheless, the significance of the pressure fluctuation inside the double-suction centrifugal pump, which is getting more and more prominent under the soaring demands for low noise and comfortable living environment, could not be underestimated. Consequently, how to reduce the pressure fluctuation as far as possible and enhance the running stability of the pump is always the research hotspot. In this study, the double-suction centrifugal impeller with abominable vibration performance is redesigned to improve the internal flow and reduce the flow-induced noise. What’s addition, the two redesigned impellers wearing splitter blades were compared in staggered arrangement with different angles for the purpose of ulteriorly decreasing the pressure fluctuation. On the basis of Realizable k-ε model and SIMPLEC algorithm, the unsteady Reynolds-averaged Navier-Stokes equations (URANS) were resolved by means of CFD simulation and the flow performance and the vibration performance were validated with the experiments. The results illustrate that the redesigned impeller with multi-blade could raise the hydraulic performance and reduce the pressure fluctuation inside the pump. When the impeller of each side was laid with the staggered angle of 12 degrees, the pressure distribution tended to be more uniform and the pressure fluctuation was well ameliorated. Through the pressure fluctuation analysis in time domain and frequency domain, the pressure change inside the pumps could be evaluated quantitatively and accurately, hence different pumps could be contrasted in detail. The consequences of this paper could provide reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps as well as other vane pumps.

Effects of Trailing Edge Position of Splitter Blade on the Pressure Pulsation in a Low Specific Centrifugal Pump

2019 ◽  
Author(s):  
Jinfeng Zhang
Keyword(s):  
Velocity Distribution ◽  
Turbulence Intensity ◽  
Pressure Fluctuation ◽  
Relative Velocity ◽  
Pressure Pulsation ◽  
Suction Side ◽  
Maximum Pressure ◽  
Trailing Edge ◽  
Flow Rates ◽  
Pulsation Amplitude

Abstract A combination of experimental and numerical simulation was carried out to analyze influence of trailing edge position of splitter blade on the pressure fluctuation in low specific pumps with and without splitter blades under different flow rates. Performance experiments and PIV tests were performed to verify the results of numerical calculation. Several monitor points were placed in the calculation model pump to collect the pressure fluctuation signals, which were processed by Fast Fourier Transform to obtain the frequency results for further analysis. Besides, turbulence intensity and relative velocity distribution were also analyzed in regions of impeller and volute. The results showed that compared with prototype without splitter blade and the splitter blade schemes, when the trailing edge of splitter blade deviates to the suction side of main blade, the maximum pressure pulsation amplitudes are the lowest at different monitoring points of model pump. And the variation of pressure pulsation amplitude in this scheme is relatively stable with the change of flow rates compared with other schemes. Furthermore, the splitter blade scheme with an appropriate trailing edge position has the lowest average turbulence intensity and optimal relative velocity distribution in main flow passage component. Therefore, this paper proposes a reference scheme of the trailing edge position of the splitter blade to effectively decrease predominate pressure pulsation amplitude.

Investigation of the Wake Effect From the Centrifugal Splitter Impeller Blade to the Vaned Diffuser

2012 ◽  
Author(s):  
Xuechen Li ◽  
Guang Xi ◽  
Jiang Hua ◽  
Wuqi Gong
Keyword(s):  
Flow Characteristics ◽  
Suction Side ◽  
Wake Flow ◽  
Centrifugal Impeller ◽  
Wake Effect ◽  
Impeller Blade ◽  
Vaned Diffuser ◽  
Side Pressure ◽  
Unsteady Wake ◽  
Impeller Outlet

In this paper, the unsteady wake effect from an unshrouded centrifugal impeller with splitter blades was numerically and experimentally investigated. The numerical simulated detail flow characteristics of two stations, respectively placed at the impeller outlet and the diffuser inlet, were compared with the measured data. The “jet-wake” flow pattern was observed at the exit of the impeller. And the investigation showed that the wake effect of the splitter was weaker that of the main blade. But both the main blade and the splitter blade wake could affect the diffuser performance at a range of whole-chord length and they provoked the pressure side profile pressure fluctuating intensely from 10% chord to 50% chord, while the suction side pressure varying rapidly at the range from 60% chord to 80% chord.

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.

scholarly journals Unsteady Pressure Pulsation and Rotating Stall Characteristics in a Centrifugal Pump with Slope Volute

2014 ◽  
Vol 6 ◽  
pp. 710791 ◽  
Author(s):  
Ning Zhang ◽  
Minguan Yang ◽  
Bo Gao ◽  
Zhong Li ◽  
Dan Ni
Keyword(s):  
Centrifugal Pump ◽  
Working Conditions ◽  
Pressure Pulsation ◽  
Cell Structure ◽  
Excitation Frequency ◽  
Suction Side ◽  
Simulation Method ◽  
Rotating Stall ◽  
Flow Rates ◽  
Unsteady Pressure

Unsteady flow structures can lead to severe vibration in centrifugal pump if the eigenfrequency of the rotor is equal to excitation frequency. In order to reduce rotor-stator interaction in centrifugal pump, a special slope volute was proposed. This paper explores the use of numerical simulation method to illustrate unsteady pressure pulsation and rotating stall characteristics under 0.05ΦN–1.4ΦN working conditions. Spectrums of pressure pulsation signals at different flow rates were analyzed. Relative velocity distributions interior blade channels were also studied to clarify correlation between flow structure and pressure spectrum. At high flow rates, predominant components in pressure spectrums always correspond to blade passing frequency ( fBPF). With decreasing of flow rate, partial flow separates from suction side of blade at 0.6ΦN, but the separate structure has little impact on pressure spectrum. From 0.8ΦN to 0.6ΦN, peak values in pressure spectrums are still located at fBPF. At rotating stall working conditions, multiple vortex structures exist in impeller, which develop with rotating impeller showing intensive unsteady properties. And partial blade channels are blocked severely. Due to the unsteady stall cell structure, stall frequencies are generated in pressure spectrum, and the excitation frequencies are different at variable flow rates.

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.

Improve of Unsteady Pressure Pulsation Based On Jet-Wake Suppression for a Low Specific Centrifugal Pump

2021 ◽  
Author(s):  
Chengshuo Wu ◽  
Qianqian Li ◽  
Feng Zheng ◽  
Peng Wu ◽  
Shuai Yang ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Dynamic Performance ◽  
Internal Flow ◽  
Work Capacity ◽  
Wake Flow ◽  
Entropy Generation Rate ◽  
Wake Structure ◽  
Unsteady Pressure ◽  
Impeller Outlet

Abstract In this study, three impellers with different blade pressure side (PS) profiles were designed and the influence on the hydraulic and dynamic performance of a low specific speed centrifugal pump was investigated by numerical simulation and experimental research. The result shows that blade PS modification introduced in this study can efficiently alleviate the unsteady pressure pulsation of pump. In order to study the effects of blade modification on the internal flow filed, the volute domain was replaced by an even outlet region for CFD analysis. Relative velocity distribution was extracted to visualize the three-dimensional (3-D) flow characteristics at the impeller outlet. The result shows that the flow at impeller outlet presents a typical jet-wake structure which is significantly suppressed after the blade modification. The suppression of jet-wake structure, which is attributed to the redistribution of pressure and velocity in the impeller caused by the change of blade work capacity can directly reduce the intensity of pressure pulsation in the volute by increasing the velocity uniformity at impeller outlet. Given that the existence of jet-wake flow results in large mixing loss and velocity deviation at the impeller outlet, entropy generation rate and slip velocity calculation were introduced here to measure the extent of jet-wake configuration. Result shows that both indicators introduced here can be used to quantify the extent of the wake-jet structure at impeller outlet, and thus, indirectly predict the strength of unsteady pressure pulsation in pump volute.

scholarly journals Experimental Investigation of Pressure Fluctuation, Vibration, and Noise in a Multistage Pump

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Kai Wang ◽  
Zixu Zhang ◽  
Chen Xia ◽  
Zhongchun Liu
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Noise Level ◽  
Pressure Pulsation ◽  
Design Flow ◽  
Monitoring Point ◽  
Characteristic Frequencies ◽  
Noise Characteristics ◽  
The Difference

In order to measure the pressure pulsation, vibration, and noise characteristics of multistage centrifugal pump in different flow rates, a five-stage centrifugal pump was chosen as research object. The results show that the main frequency of pressure pulsation was BPF1, 9APF, BPF2, BPF2, and 9APF. According to the order of monitoring points, the intensity of the pressure fluctuation increased and then decreased, with the strongest fluctuation at monitoring point P2. The peak value of pressure fluctuation in monitoring point P2 was obviously higher than the other monitoring points. The main characteristic frequency of vibration is 4APF, BPF2, 9APF, 2BPF2, 3BPF1, 4BPF1, and 4BPF2. The number of characteristic frequencies at the outlet flange was significantly more than the number of characteristic frequencies at the inlet flange. As the flow rate increased, the vibration of motor gradually increased and the vibration of pump increased at first and then decreased. It reached the minimum vibration level in the design flow rate. Motor contributed the largest amount of noise caused by the pump unit. The noise level of measure point which is close to motor is higher than that of other measure points. As the flow rate increased, the noise incrementally increased, and the difference in noise level between measure points decreased gradationally. When the flow rate was 120 m3/h, the maximum difference value of different noise monitoring points was only 1.7 dB.

The Development of Wake Flow in a Centrifugal Impeller

1980 ◽  
Vol 102 (2) ◽  
pp. 382-389 ◽  
Author(s):  
M. W. Johnson ◽  
J. Moore
Keyword(s):  
Three Dimensional ◽  
Suction Side ◽  
Secondary Flows ◽  
Wake Flow ◽  
Centrifugal Impeller ◽  
Three Dimensional Flow ◽  
Cross Sectional ◽  
Flow Measurements ◽  
Compressor Impeller ◽  
Rotating Impeller

Three-dimensional flow, leading to the formation and the growth of a wake in a centrifugal impeller, has been studied. Results of flow measurements in a 1 m dia, shrouded, centrifugal compressor impeller running at 500 rpm are presented. Relative velocities and rotary stagnation pressures (p* = p + 1/2ρW2 − 1/2ρω2r2) were measured, on five cross-sectional planes between the inlet and outlet of the impeller, using pressure probes which were traversed within the rotating impeller passage. Particular attention was given to the convection of low p* fluid by secondary flows and to the formation of the wake in the shroud/suction-side corner region of the passage.

Study on the Influence of Centrifugal Pump Inlet Flow Field Instability and Methods of Adjustment

2019 ◽  
Author(s):  
Bo Qian ◽  
Jinping Chen ◽  
Peng Wu ◽  
Bin Huang ◽  
Dazhuan Wu
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Flow Instability ◽  
Wake Flow ◽  
Experimental Investigations ◽  
Inlet Flow ◽  
Inlet Tube ◽  
Fluctuation Amplitude ◽  
Pump Inlet

Abstract The quality of centrifugal pump inlet flow field is an important factor that affecting the performance of pump. Studies have proved that the vortex in the inlet area can also bring an extra flow instability to pump, which results in a hydro-induced vibration. This phenomenon is more common and significant in the pumps with an elbow tube, which is often applied to minimize installation size, before pump inlet. Therefore, it is necessary to look into the influence of inlet flow field instability on pump performance especially the vibration performance. The methods of adjusting pump inlet flow field is also worthy of being studied in the meantime. In this study, the influence of inlet vortex on the performance of centrifugal pump with an elbow inlet tube is investigated by means of CFD analysis. The flow is significantly affected when going through the elbow tube inlet and then turbulence is generated as a result, which enters the impeller at the next moment. The turbulence brings an asymmetrical flow condition at the impeller suction area, which can intensify pressure pulsation and hydro-induced vibration. In order to reduce the turbulence, two modifications on the elbow inlet tube are investigated in this study. A specially designed vane is deployed inside the inlet tube in the MOD1, and the MOD2 is added with two splitter vanes on the basis of the MOD1. The turbulent flow in the elbow inlet tube can be reordered as it is controlled by the vanes. The difference on pump performances that the inlet vane has made is specifically simulated and compared. The flow fields of the inlet tube influenced by the vane is also investigated on the vortex distribution and velocity vector distribution. The MOD1 has a generally smaller pressure fluctuation amplitude than the prototype in the impeller inlet area while the pressure fluctuation amplitude of the MOD2 in the impeller inlet area is stronger than the prototype. It is considered as a consequence of multiple effects, which are, the rise of velocity because of flow area replacement by the vanes making the flow field less stable as well as the wake flow induced by the vanes increasing the instability of the flow field. Therefore, although the flat vanes can help adjusting the flow field, their negative influences also act in the opposite way. It is worthwhile to find the balance between the benefits and the costs in flow field stability of installing adjusting vanes. The selection of parameter, number and installation position needs to be further investigated. The numerical results of the MOD1 are also validated through experimental investigations.

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