Unsteady Turbulent Simulation and Pressure Fluctuation Analysis for Centrifugal Pumps

2009 ◽  
Vol 22 (01) ◽  
pp. 64 ◽  
Author(s):  
Shouqi YUAN
Keyword(s):  
Pressure Fluctuation ◽  
Fluctuation Analysis ◽  
Centrifugal 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.

scholarly journals Investigation on Reduction of Pressure Fluctuation for a Double-Suction Centrifugal Pump

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Qianqian Li ◽  
Shiyang Li ◽  
Peng Wu ◽  
Bin Huang ◽  
Dazhuan Wu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Fluctuation Analysis ◽  
Centrifugal Pumps ◽  
Large Power ◽  
Pressure Contour ◽  
Dimensionless Pressure ◽  
Fluctuation Amplitude ◽  
Radial Gap

AbstractDouble-suction centrifugal pumps have been applied extensively in many areas, and the significance of pressure fluctuations inside these pumps with large power is becoming increasingly important. In this study, a double-suction centrifugal pump with a high-demand for vibration and noise was redesigned by increasing the flow uniformity at the impeller discharge, implemented by combinations of more than two parameters. First, increasing the number of the impeller blades was intended to enhance the bounding effect that the blades imposed on the fluid. Subsequently, increasing the radial gap between the impeller and volute was applied to reduce the rotor-stator interaction. Finally, the staggered arrangement was optimized to weaken the efficacy of the interference superposition. Based on numerical simulation, the steady and unsteady characteristics of the pump models were calculated. From the fluctuation analysis in the frequency domain, the dimensionless pressure fluctuation amplitude at the blade passing frequency and its harmonics, located on the monitoring points in the redesigned pumps (both with larger radial gap), are reduced a lot. Further, in the volute of the model with new impellers staggered at 12°, the average value for the dimensionless pressure fluctuation amplitude decreases to 6% of that in prototype pump. The dimensionless root-mean-square pressure contour on the mid-span of the impeller tends to be more uniform in the redesigned models (both with larger radial gap); similarly, the pressure contour on the mid-section of the volute presents good uniformity in these models, which in turn demonstrating a reduction in the pressure fluctuation intensity. The results reveal the mechanism of pressure fluctuation reduction in a double-suction centrifugal pump, and the results of this study could provide a reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps and other pumps.

Experimental Investigation of Pressure Fluctuations on Inner Wall of a Centrifugal Pump

2019 ◽  
Vol 36 (4) ◽  
pp. 401-410 ◽  
Author(s):  
Xiao-Qi Jia ◽  
Bao-Ling Cui ◽  
Zu-Chao Zhu ◽  
Yu-Liang Zhang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
High Flow ◽  
Low Flow ◽  
Centrifugal Pumps ◽  
Flow Rates ◽  
Pressure Distributions ◽  
Blade Passing Frequency

Abstract Affected by rotor–stator interaction and unstable inner flow, asymmetric pressure distributions and pressure fluctuations cannot be avoided in centrifugal pumps. To study the pressure distributions on volute and front casing walls, dynamic pressure tests are carried out on a centrifugal pump. Frequency spectrum analysis of pressure fluctuation is presented based on Fast Fourier transform and steady pressure distribution is obtained based on time-average method. The results show that amplitudes of pressure fluctuation and blade-passing frequency are sensitive to the flow rate. At low flow rates, high-pressure region and large pressure gradients near the volute tongue are observed, and the main factors contributing to the pressure fluctuation are fluctuations in blade-passing frequency and high-frequency fluctuations. By contrast, at high flow rates, fluctuations of rotating-frequency and low frequencies are the main contributors to pressure fluctuation. Moreover, at low flow rates, pressure near volute tongue increases rapidly at first and thereafter increases slowly, whereas at high flow rates, pressure decreases sharply. Asymmetries are observed in the pressure distributions on both volute and front casing walls. With increasing of flow rate, both asymmetries in the pressure distributions and magnitude of the pressure decrease.

scholarly journals Agglomeration detection by pressure fluctuation analysis during Cynara cardunculus L. gasification in a fluidized bed

2016 ◽  
Vol 284 ◽  
pp. 640-649 ◽  
Author(s):  
Jesús Gómez-Hernández ◽  
Daniel Serrano ◽  
Antonio Soria-Verdugo ◽  
Sergio Sánchez-Delgado
Keyword(s):  
Fluidized Bed ◽  
Pressure Fluctuation ◽  
Fluctuation Analysis ◽  
Cynara Cardunculus

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.

Influence of wall roughness on the static performance and pressure fluctuation characteristics of a double-suction centrifugal pump

2018 ◽  
Vol 232 (7) ◽  
pp. 826-840 ◽  
Author(s):  
Zhifeng Yao ◽  
Min Yang ◽  
Ruofu Xiao ◽  
Fujun Wang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Design Flow ◽  
Experimental Investigations ◽  
Wall Roughness ◽  
Detached Eddy Simulation ◽  
Centrifugal Pumps ◽  
Eddy Simulation ◽  
Static Performance

The unsteady flow field and pressure fluctuations in double-suction centrifugal pumps are greatly affected by the wall roughness of internal surfaces. To determine the wall roughness effect, numerical and experimental investigations were carried out. Three impeller schemes for different wall roughness were solved using detached eddy simulation, and the performance and pressure fluctuations resolved by detached eddy simulation were compared with the experimental data. The results show that the effects of wall roughness on the static performance of a pump are remarkable. The head and efficiency of the tested double-suction centrifugal pump are raised by 2.53% and 6.60% respectively as the wall roughness is reduced by means of sand blasting and coating treatments. The detached eddy simulation method has been proven to be accurate for the prediction of the head and efficiency of the double-suction centrifugal pump with roughness effects. The influence of the roughness on pressure fluctuation is greatly dependent on the location relative to the volute tongue region. For locations close to the volute tongue, the peak-to-peak value of the pressure fluctuations of a wall roughness of Ra = 0.10 mm may be 23.27% larger than the case where Ra = 0.02 mm at design flow rate.

Estimation of the minimum spouting velocity based on pressure fluctuation analysis

2020 ◽  
Vol 113 ◽  
pp. 56-65
Author(s):  
Ronaldo Correia de Brito ◽  
Mikel Tellabide ◽  
Idoia Estiati ◽  
José Teixeira Freire ◽  
Martin Olazar
Keyword(s):  
Pressure Fluctuation ◽  
Fluctuation Analysis

Fluidization, Mixing and Segregation of a Biomass-Sand Mixture in a Fluidized Bed

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Yong Zhang ◽  
Baosheng Jin ◽  
Wenqi Zhong
Keyword(s):  
Fluidized Bed ◽  
Pressure Fluctuation ◽  
Visual Observation ◽  
Fluctuation Analysis ◽  
Mixing Ratio ◽  
Dynamic Features ◽  
Pressure Transducers ◽  
Sand Mixture ◽  
Wide Range ◽  
Initial Packing

Fluidization, mixing and segregation of a biomass-sand mixture in a 3D gas-fluidized bed have been investigated by means of visual observation, pressure fluctuation analysis and the bed-frozen method. Three types of mixtures are considered, in which biomass is a thin long stalk, and sand belongs to the Geldart B category. Experiments are carried out in a segmented fluidized bed equipped with multiple pressure transducers. Three initial packing conditions and two experiment procedures are used. The fluidization velocity varies to cover a wide range. Results show that in the local fluidization region, the mixing and segregation patterns are sensitive to the initial packing condition. In the case of a fully segregated state with biomass at the bottom, the bed inversion can be significantly observed due to the great segregation tendency of biomass. Further analyses indicate that the mixing ratio exerts a subtle influence on the competition between mixing and segregation by disturbing the coalescence and break-up of the bubble. In addition, the pressure fluctuation signal proves to be helpful in understanding the dynamic features of the phenomenology.

scholarly journals Numerical Investigation of Periodically Unsteady Pressure Field in a High Power Centrifugal Diffuser Pump

2014 ◽  
Vol 6 ◽  
pp. 159380 ◽  
Author(s):  
Ji Pei ◽  
Wenjie Wang ◽  
Shouqi Yuan ◽  
Jieyun Mao
Keyword(s):  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Heat Removal ◽  
Centrifugal Pumps ◽  
Unsteady Pressure ◽  
Fluctuation Intensity ◽  
Rotor Stator Interaction ◽  
Operational Flow ◽  
Downstream Flow ◽  
Pressure Characteristics

Pressure fluctuations are the main factors that can give rise to reliability problems in centrifugal pumps. The periodically unsteady pressure characteristics caused by rotor-stator interaction have been investigated by CFD calculation in a residual heat removal pump. Side chamber flow effect is also considered for the simulation to accurately predict the flow in whole flow passage. The pressure fluctuation results in time and frequency domains were considered for several typical monitoring points in impeller and diffuser channels. In addition, the pressure fluctuation intensity coefficient (PFIC) based on standard deviation was defined on each grid node for entire space and impeller revolution period. The results show that strong pressure fluctuation intensity can be found in the gap between impeller and diffuser. As a source, the fluctuation can spread to the upstream and downstream flow channels as well as the side chamber channels. Meanwhile, strong pressure fluctuation intensity can be found in the discharge tube of the circular casing. In addition, the obvious influence of operational flow rate on the PFIC distribution can be found. The analysis indicates that the pressure fluctuations in the aspects of both frequency and intensity can be used to comprehensively evaluate the unsteady pressure characteristics in centrifugal pumps.

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