Effects of Blade Pressure Side Modification On Unsteady Pressure Pulsation and Flow Structures in a Centrifugal Pump

2021 ◽  
Author(s):  
Chengshuo Wu ◽  
Wenqi Zhang ◽  
Peng Wu ◽  
Jiale Yi ◽  
Haojie Ye ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Internal Flow ◽  
Flow Structures ◽  
Pressure Side ◽  
Unsteady Pressure ◽  
Operation Conditions ◽  
Impeller Outlet ◽  
Steady State Simulation

Abstract In this paper, the effects of modifying the blade pressure side on unsteady pressure pulsation and flow structures in a low specific speed centrifugal pump are carried out by experimental and CFD. Seven monitor points are arranged in the circumferential direction of the impeller outlet to capture the pressure signals in the volute at the flow rate of 0.2-1.6Qd. Results show that blade PS modification introduced here can significantly alleviate the amplitude of pressure pulsation at blade passing frequency in all concerned operation conditions. The volute domain is replaced by an even outlet region for CFD analysis to study the effects on internal flow field. The SST turbulence model is adopted for steady-state simulation while the DDES based on the SST approach is adopted for transient simulation. Results show that local velocity fluctuation is the dominant reason for pressure pulsation in the volute. After PS modification, the relative velocity distribution at impeller outlet is more uniform and the intensity of shedding vortex at the blade trailing edge decreases significantly. The change of internal flow structure improves the uniformity of circumferential velocity distribution at downstream of impeller outlet, which leads to the decrease of pressure fluctuation amplitude in the volute. Meanwhile, the Local Euler Head distribution and the blade loading of PS are presented and compared. Results show that the reduction of pressure pulsation attributes to the more uniform energy distribution at impeller outlet which is achieved by actively unloading the PS of the modified blades.

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.

Effects of the staggered blades on unsteady pressure pulsations and flow structures of a centrifugal pump

2021 ◽  
pp. 095765092098732
Author(s):  
Ning Zhang ◽  
Bo Gao ◽  
Chao Li ◽  
Dan Ni ◽  
Guoping Li
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Pulsation ◽  
Second Harmonic ◽  
Simulation Method ◽  
Pump Efficiency ◽  
Pressure Amplitude ◽  
Pressure Pulsations ◽  
Unsteady Pressure ◽  
Negative Effect

Effects of the staggered blades on unsteady pressure pulsations of a centrifugal pump with a specific speed ns=147 are investigated by the numerical simulation method. The obtained results are compared with the original blades. To clarify the resulting effects, eight monitoring points are used to extract pressure signals at three typical working conditions, and component at the blade passing frequency fBPF is emphasized. Results show that the pump efficiency and head will be reduced by the staggered blades, and at the nominal flow rate, the reduction is about 1.5% from comparison with the original blades. For all the eight points, the staggered blades contribute to the reduction of pressure amplitudes at fBPF when the pump works at three flow rates. The averaged reduction is 15.5% at the nominal flow rate. However, the negative effect on the second harmonic of fBPF will be caused by the staggered blades, and the corresponding pressure amplitude will increase at 2fBPF. It means that the pressure pulsation energy will be redistributed among the discrete components in pressure spectrum by the staggered blades. From the TKE distribution, it is found that the TKE values on the blade pressure side will be significantly affected by the staggered blades.

scholarly journals Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1408 ◽  
Author(s):  
Bin Huang ◽  
Guitao Zeng ◽  
Bo Qian ◽  
Peng Wu ◽  
Peili Shi ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Trailing Edge ◽  
Impeller Blade ◽  
Blade Passing Frequency ◽  
Impeller Outlet ◽  
Edge Profile ◽  
Edge Trimming

The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.

scholarly journals Investigation of Unsteady Pressure Pulsation in New Type Dishwasher Pump with Special Double Tongue Volute

2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Jinfeng Zhang ◽  
Yilei Zhu ◽  
Yalin Li ◽  
Ping Huang ◽  
Hui Xu ◽  
...  
Keyword(s):  
Pressure Pulsation ◽  
Rotation Speed ◽  
Performance Tests ◽  
Unsteady Pressure ◽  
Passive Rotation ◽  
Impeller Outlet ◽  
Tongue Position ◽  
New Type ◽  
Reference Scheme ◽  
Blade Frequency

Through numerical simulations, this work analyzes the unsteady pressure pulsation characteristics in new type of dishwasher pump with double tongue volute and single tongue volute, under volute static and rotation conditions. Likewise, the performance tests were also carried out to verify the numerical results. Multiple monitoring points were set at the various positions of new type dishwasher pump to collect the pressure pulsation signals, and the relevant frequency signals were obtained via Fast Fourier Transform, to analyze the influence of volute tongue and its passive speed on the pump performance. The results reveal that when the double tongue volute is stationary, the pressure pulsation amplitudes increase from the impeller inlet to the impeller outlet. Under the influence of shedding vortex, the pressure pulsation in the lateral region of tongue becomes disorganized, and the main frequency of pressure pulsation changes from blade frequency to shaft frequency. In addition, compared with the static volute, double tongue volute can effectively guide the water flow out of the tongue during the rotation process, thus ensuring good periodicity for pressure pulsation in the tongue region. Accordingly, a volute reference scheme with passive rotation speed is proposed in this study, which can effectively improve the pressure pulsation at tongue position, and provides a new idea for rotor-stator interference to guide the innovation of dishwasher.

Study and Investigation on the Mach of Impeller Outlet and Diffuser Inlet in Stamping and Welding Centrifugal Pump

2012 ◽  
Vol 229-231 ◽  
pp. 2454-2458
Author(s):  
Jian Jun Gan ◽  
Jie Gang Mou ◽  
Shui Hua Zheng ◽  
Bo Zhu
Keyword(s):  
Centrifugal Pump ◽  
Experimental Research ◽  
Static Pressure ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Area Ratio ◽  
Cfd Simulations ◽  
Impeller Outlet ◽  
And Performance

Based on CFD simulations and experimental research, this paper studied the mach of impeller outlet and diffuser inlet in stamping and welding centrifugal pump. The influence of area ratio Y of impeller outlet to diffuser inlet on pump internal flow characteristics and performance was studied. Five different area ratio pump models were analyzed. The results indicate that as the area ratio Y= F3/F2 increase, the velocity of fluid in diffuser inlet decreases continuously, the average static pressure of diffuser outlet increases, and the head and efficiency of the pump are risen. When the area ratio increases from Y=1.48 to Y=3.49, the head increases about 3.0% and the efficiency about 2.0%.

Influence of grooved volute casing parameters on pressure pulsation and erosion wear characteristics in a centrifugal pump

2022 ◽  
Author(s):  
Zhengjing Shen ◽  
Wei Han ◽  
Yiming Zhong ◽  
Bo Luo ◽  
Rennian Li ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Internal Flow ◽  
Phase Flow ◽  
Erosion Wear ◽  
Flow Conditions ◽  
Two Phase ◽  
Wear Characteristics ◽  
Groove Structure ◽  
Solid Liquid

Previous work has shown that performance and internal flow characteristics of a centrifugal pump can be significantly improved with grooved volute casing (GVC). However, it has been found that the selection of the design parameters of the groove structure also has a direct impact on the performance output, internal flow pressure pulsation and erosion wear characteristics of the overflow components of centrifugal pump, so it is necessary to further analyze the design rules of the groove structure parameters. In this study, we first investigated the influence of the number of grooves on the head, efficiency and unsteady pressure pulsation characteristics of the internal flow field of the centrifugal pump, and on this basis, the correlation between different particle parameters and the erosion wear of key overflow components under the conditions of solid–liquid two-phase flow were also studied, and the erosion wear characteristics of the inner wall of the volute casing of centrifugal pump with GVC and original volute casing (OVC) structures were compared. This research leads to the conclusion that when the number of grooves is 3, the groove structure has the least influence on the performance of the centrifugal pump, and the overall change of the performance curve is more stable. Additionally, the pressure pulsation at each monitoring point of the GVC under the same flow condition is smaller, and when the number of grooves increases, the pressure pulsation amplitude also decreases. When the number of grooves is 3, the GVC shows a more significant flow improvement effect under all flow conditions. Based on the improvement of the groove structure on the flow stability, the particle motion behavior can be affected at the same time, so that the pump with GVC can mitigate the erosion wear of the inner wall of the volute casing under the solid–liquid two-phase flow conditions, which improves the critical performance and service life of the key overflow components of the pump.

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.

A Design Method of Aero Fuel Centrifugal Pump with Integrated Inducer and Impeller

2014 ◽  
Vol 680 ◽  
pp. 303-306
Author(s):  
Jia Li ◽  
Hua Cong Li ◽  
Jiang Feng Fu ◽  
Shu Hong Wang
Keyword(s):  
Centrifugal Pump ◽  
Simulation Analysis ◽  
Design Method ◽  
Internal Flow ◽  
Field Performance ◽  
Simulation Method ◽  
Hybrid Network ◽  
Control Technique ◽  
Pressure Side ◽  
Flow Conditions

With the development of the aero engine control technique, aero fuel centrifugal pump with integrated inducer and impeller meet the requirements better than the divided pump. This paper established the hybrid network of the centrifugal pump which adopted multi-block topology structure and octree format, analyzed the internal flow field performance of the pump based on numerical simulation. The simulation datas compared with test datas show that under different calculation conditions, head error of the simulation data and experimental data is less than 1%, and the efficiency value of error is less than 5%. The simulation method can accurately calculate the performance of the pump. The simulation analysis shows that the asymmetry of the impeller internal pressure is appreciable under different flow conditions because of the inlet length, under other small flow conditions. The most dramatic change is the pressure in the impeller channel, and the pressure under large flow conditions is lower than that under other flow conditions. In fixed location of the pressure side, there may produce low speed flow group, the situation is the same as in the entrance to the attachment of back pressure side.

Influence of blade leaning on hydraulic excitation and structural response of a reversible pump turbine

2021 ◽  
pp. 095765092110349
Author(s):  
Jinhui Ouyang ◽  
Yongyao Luo ◽  
Ran Tao
Keyword(s):  
High Efficiency ◽  
Pressure Pulsation ◽  
Guide Vane ◽  
Equivalent Stress ◽  
Structural Response ◽  
Internal Flow ◽  
Pressure Side ◽  
Pump Mode ◽  
Runner Design ◽  
Turbine Mode

Blade leaning is commonly seen in the runner design of reversible pump turbines which operate under varying conditions. However, there is no certain law in determine the leaning mode and level. Considering performance, hydraulic excitation and structural response, five runners with strong rotational (RL+), rotational (RL), strong counter-rotational (CL+), counter-rotational (CL) and without (NL) blade leaning are compared under high-efficiency condition in pump mode and turbine mode. The head, efficiency, internal flow pressure pulsation and runner stress are comparatively studied. Among the five runners, CL+ runner is found has the highest efficiency as pump when RL+ runner has the highest efficiency as turbine. Pressure pulsation results show that the rotor-stator interaction region is the strongest pulsation source especially for runner and blade frequencies. In pump mode, pressure pulsation intensity decreases when blade leaning mode gradually changes from rotational to counter-rotational. In turbine mode, the NL runner has the strongest pressure pulsation intensity in runner and guide vane. Both rotational and counter-rotational leaning will reduce pressure pulsation. Velocity contours indicate that blade leaning will affect the velocity uniformity especially along rotational direction and cause stronger or weaker local hydraulic excitation. Under hydraulic excitation, RL+ runner suffers the highest equivalent stress as pump while CL runner suffers the highest equivalent stress as turbine. From rotational to counter-rotational blade leaning, the maximum stress moves on the crown from low pressure side to high pressure side. Considering hydraulic excitation and structural response, the strong counter-rotational leaning blade is found better in reversible runner design.

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