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.

Numerical investigation of the effects of splitter blade deflection on the pressure pulsation in a low specific speed centrifugal pump

2019 ◽  
Vol 234 (4) ◽  
pp. 420-432 ◽  
Author(s):  
Jinfeng Zhang ◽  
Guidong Li ◽  
Jieyun Mao ◽  
Shouqi Yuan ◽  
Yefei Qu ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Turbulence Intensity ◽  
Pressure Fluctuation ◽  
Relative Velocity ◽  
Pressure Pulsation ◽  
Maximum Pressure ◽  
Flow Rates ◽  
Pulsation Amplitude ◽  
Low Specific Speed ◽  
Specific Speed

A combination of experimental and numerical simulation was carried out to analyze the influences of the splitter blade deflection on the performance and pressure fluctuation in low specific speed pumps with and without splitter blades under different flow rates. Performance experiments and particle image velocimetry (PIV) tests were performed to verify the results of the numerical calculation. Several monitoring 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. In addition, turbulence intensity and relative velocity distribution were also analyzed in the regions of the impeller and volute. The results showed that compared with a prototype without a splitter blade and the splitter blade schemes, the maximum pressure pulsation amplitudes are the lowest at different monitoring points of the model pump when the splitter blade deflects to the suction side of the main blade. The variation of pressure pulsation amplitude in this scheme is relatively stable with the change of flow rates compared with other schemes. Furthermore, the impeller scheme with an appropriate deflection of the splitter blade has the lowest turbulence intensity and optimal relative velocity distribution in the main flow passage. Therefore, this paper proposes a reference scheme of the impeller with the splitter blade to effectively decrease the predominate pressure pulsation amplitude.

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.

Influence of the Blade Trailing Edge Profile on the Performance and Unsteady Pressure Pulsations in a Low Specific Speed Centrifugal Pump

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Bo Gao ◽  
Ning Zhang ◽  
Zhong Li ◽  
Dan Ni ◽  
MinGuan Yang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Pressure Pulsations ◽  
Trailing Edge ◽  
Unsteady Pressure ◽  
Pulsation Amplitude ◽  
Trailing Edges ◽  
Edge Profile ◽  
Low Specific Speed ◽  
Specific Speed

The blade trailing edge profile is of crucial importance for the performance and pressure pulsations of centrifugal pumps. In the present study, numerical investigation is conducted to analyze the effect of the blade trailing edge profile influencing the performance and unsteady pressure pulsations in a low specific speed centrifugal pump. Five typical blade trailing edges are analyzed including original trailing edge (OTE), circle edge (CE), ellipse on pressure side (EPS), ellipse on suction side (ESS), and ellipse on both sides (EBS). Results show that the well-designed blade trailing edges, especially for the EPS and EBS profiles, can significantly improve the pump efficiency. Pressure amplitudes at fBPF and 2fBPF are together calculated to evaluate the influence of the blade trailing edge profile on pressure pulsations. The EPS and EBS profiles contribute obviously to pressure pulsations reduction. In contrast, the CE and ESS profiles lead to increase of pressure pulsation amplitude compared with the OTE pump. Vorticity distribution at the blade trailing edge demonstrates that the EPS and EBS profiles have an effective impact on reducing vortex intensity at the blade trailing edge. Consequently, rotor–stator interaction could be attenuated leading to lower pressure pulsation amplitude. It is thought to be the main reason of pressure pulsations reduction obtained with the proper modified blade trailing edges. The results would pave the way for further optimization of the blade trailing edge profile.

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.

scholarly journals The Role of Blade Sinusoidal Tubercle Trailing Edge in a Centrifugal Pump with Low Specific Speed

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 625 ◽  
Author(s):  
Bowen Li ◽  
Xiaojun Li ◽  
Xiaoqi Jia ◽  
Feng Chen ◽  
Hua Fang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Suction Side ◽  
High Amplitude ◽  
Pressure Pulsations ◽  
Trailing Edge ◽  
Low Specific Speed ◽  
Specific Speed ◽  
And Performance ◽  
The Impact

Pressure pulsations may cause high-amplitude vibrations during the process of a centrifugal pump. The trailing edge shape of the blade has a critical influence on the pump’s pressure fluctuation and hydraulic characterization. In this paper, inspired by the humpback whale flipper, the authors research the impact of applying the sinusoidal tubercles to the blade suction side of the trailing edge. Numerical calculation and experiments are carried out to investigate the impact of the trailing edge shape on the pressure pulsations and performance of a centrifugal pump with low specific speed. Two designed impellers are tested, one is a sinusoidal tubercle trailing edge (STTE) impeller and the other is the original trailing edge (OTE) prototype. The detailed study indicates that the sinusoidal tubercle trailing edge (STTE) reduces pressure pulsation and enhances hydraulic performance. In the volute tongue region, the pressure pulsation amplitudes of STTE at fBPF decrease significantly. The STTE impeller also effectively changes the vortex structure and intensity in the blade trailing edge area. This investigation will be of great benefit to the optimal design of pumps.

scholarly journals Numerical Analysis of Pressure Pulsation for a Bidirectional Pump under Positive and Reverse Operation

2014 ◽  
Vol 6 ◽  
pp. 730280 ◽  
Author(s):  
Pengfei Ma ◽  
Jun Wang ◽  
Hui Li
Keyword(s):  
Pressure Pulsation ◽  
Guide Vane ◽  
Rotation Frequency ◽  
Great Promise ◽  
Variation Principle ◽  
Maximum Pressure ◽  
Valuable Insight ◽  
Pulsation Frequency ◽  
Pulsation Amplitude ◽  
Wide Range

Bidirectional pump holds great promise in a wide range of applications since it could realize the function of drainage and irrigation simultaneously. A bidirectional pump with high specific speed was designed and 10 groups of performance tests, under different setting angles, including both positive and negative directions, were conducted. Numerical simulations were then performed to analyze the variation principle of internal pressure pulsation in flow passage and both the front and the back sides of the blade and guide vane. Results show that the optimum operation point was shifted and the performance declined under reverse operation. The maximum pressure pulsation amplitude occurred to the vicinity of the blade's inlet edge under both positive and negative operations. The main pulsation frequency was the blade passing frequency while it was four times of shaft rotation frequency in the rotatory zone, which was equal to the number of guide vanes. The guide vane has a significant effect on the pressure pulsation variation. The pulsation amplitude had a higher value while the pump was in its negative operation rather than positive. These results could provide valuable insight for reducing the pressure amplitudes in the bidirectional pump.

Study on Pressure Pulsation in the Volute of a Centrifugal Pump by Large Eddy Simulation

2014 ◽  
Author(s):  
Yuan Zhang ◽  
Yongxue Zhang ◽  
Jinya Zhang ◽  
Hucan Hou
Keyword(s):  
Large Eddy Simulation ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Stable Operation ◽  
Flow Rates ◽  
Eddy Simulation ◽  
Pulsation Amplitude ◽  
Blade Passing Frequency ◽  
Large Eddy

Pressure pulsation caused by unsteady flow plays one of the most important roles in the stable operation of centrifugal pumps. Numerical simulation method of LES (Large Eddy Simulation) with WALE model has been used to calculate the unsteady flow in IS150-125-250 centrifugal pump passages. Three groups monitoring points distributed on 8 cross sections in different radial, circumferential, axial directions were set. And pressure pulsation in volute with different flow rates, radial distance, circumferential angles and axial distance was studied. Changing of the maximal pressure pulsation amplitude on monitoring points has been obtained by time and frequency domain analysis. The research demonstrated the maximum amplitude of pressure pulsation is located at the volute tongue, and its magnitude changes with flow rates at each monitoring point. The dominant frequency of pressure pulsation in the volute is equal to the blade passing frequency and the sub-dominant frequencies are also related to the blade passing frequency. The periodicities of circumferential pressure pulsations at different monitoring points in the volute are similar. More deviation of design flow rate results in larger pressure pulsation amplitude. Increasing radius will weaken pressure pulsation amplitude while closing to the wall of volute can strengthen the pressure pulsation. The research of pressure pulsation in volute will show great help in hydraulic design of centrifugal pump to realize longer component life, less vibration and more stable operation.

scholarly journals Investigation of Separation Phenomena in a Radial Pump at Reduced Flow Rate by Large-Eddy Simulation

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Antonio Posa ◽  
Antonio Lippolis ◽  
Elias Balaras
Keyword(s):  
Reverse Flow ◽  
Leading Edge ◽  
Suction Side ◽  
Secondary Flows ◽  
Vaned Diffuser ◽  
Flow Rates ◽  
Turbulent Statistics ◽  
Large Eddy ◽  
Radial Pump ◽  
Reduced Flow

Turbopumps operating at reduced flow rates experience significant separation and backflow phenomena. Although Reynolds-Averaged Navier–Stokes (RANS) approaches proved to be usually able to capture the main flow features at design working conditions, previous numerical studies in the literature verified that eddy-resolving techniques are required in order to simulate the strong secondary flows generated at reduced loads. Here, highly resolved large-eddy simulations (LES) of a radial pump with a vaned diffuser are reported. The results are compared to particle image velocimetry (PIV) experiments in the literature. The main focus of the present work is to investigate the separation and backflow phenomena occurring at reduced flow rates. Our results indicate that the effect of these phenomena extends up to the impeller inflow: they involve the outer radii of the impeller vanes, influencing significantly the turbulent statistics of the flow. Also in the diffuser vanes, a strong spanwise evolution of the flow has been observed at the reduced load, with reverse flow, located mainly on the shroud side and on the suction side (SS) of the stationary channels, especially near the leading edge of the diffuser blades.

Influence of tip clearance and cavity depth on heat transfer in a cutback squealer tip

2020 ◽  
pp. 095441002096469
Author(s):  
Weijie Wang ◽  
Shaopeng Lu ◽  
Hongmei Jiang ◽  
Qiusheng Deng ◽  
Jinfang Teng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Suction Side ◽  
High Heat ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Trailing Edge ◽  
Cavity Depth ◽  
High Heat Transfer ◽  
Blade Tip ◽  
High Heat Transfer Coefficient

Numerical simulations are conducted to present the aerothermal performance of a turbine blade tip with cutback squealer rim. Two different tip clearance heights (0.5%, 1.0% of the blade span) and three different cavity depths (2.0%, 3.0%, and 6.0% of the blade span) are investigated. The results show that a high heat transfer coefficient (HTC) strip on the cavity floor appears near the suction side. It extends with the increase of tip clearance height and moves towards the suction side with the increase of cavity depth. The cutback region near the trailing edge has a high HTC value due to the flush of over-tip leakage flow. High HTC region shrinks to the trailing edge with the increase of cavity depth since there is more accumulated flow in the cavity for larger cavity depth. For small tip clearance cases, high HTC distribution appears on the pressure side rim. However, high HTC distribution is observed on suction side rim for large tip clearance height. This is mainly caused by the flow separation and reattachment on the squealer rims.

scholarly journals Investigation into the Influence of Division Pier on the Internal Flow and Pulsation in the Outlet Conduit of an Axial-Flow Pump

2021 ◽  
Vol 11 (15) ◽  
pp. 6774
Author(s):  
Fan Yang ◽  
Dongjin Jiang ◽  
Tieli Wang ◽  
Pengcheng Chang ◽  
Chao Liu ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Pressure Pulsation ◽  
Axial Flow ◽  
Hydraulic Loss ◽  
Main Frequency ◽  
Starting Position ◽  
The Difference ◽  
Axial Flow Pump ◽  
Outlet Conduit ◽  
Flow Pump

The outlet conduit is an important construction connecting the outlet of the pump guide vane and the outlet pool; in order to study the hydraulic performance of the straight outlet conduit of the axial-flow pump device, this paper adopts the method of numerical simulation and analyzes the influence of the division pier on the pressure and velocity distribution inside and near the wall of the straight outlet conduit based on three design schemes. Four pressure pulsation measuring points were arranged in the straight outlet conduit, and the low-frequency pulsation characteristic information inside the straight outlet conduit with and without the division pier was extracted by wavelet packet reconstruction. The results show that the addition of a division pier has an effect on the hydraulic loss, near-wall pressure and velocity distribution in the straight outlet conduit. A small high-pressure zone is formed near the wall at the starting position of the division pier, and a large high-speed zone is formed on the left side at the starting position of the division pier. The length of the division pier has no significant effect on the flow distribution of the straight outlet conduit and the pressure and velocity distribution near the wall. Under different working conditions, each monitoring point has the maximum energy in the sub-band (0~31.25 Hz). With the increase of the flow rate, the total pressure energy of the straight outlet conduit decreases gradually. Under each condition, the difference of the energy proportion of the horizontal monitoring points of the straight outlet conduit is small, and the difference of the energy proportion of the two monitoring points at the top and bottom of the outlet channel is relatively large. The energy of the two monitoring points in the straight outlet conduit with a division pier is smaller than that of the two monitoring points in the straight outlet conduit without a division pier. There are differences in the main frequency and the power spectrum corresponding to the main frequency of the monitoring points in the straight outlet conduit, and the reasonable setting of the division pier is conducive to reducing the pressure pulsation of the flow in the straight outlet conduit and is beneficial to the safe and stable operation of the pump device.

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