Experimental Investigation of Relationship Between Pressure Fluctuations and Vibrations for a Double Suction Centrifugal Pump

2011 ◽  
Author(s):  
Zhifeng Yao ◽  
Fujun Wang ◽  
Ruofu Xiao ◽  
Chenglian He ◽  
Zhuqing Liu
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Pressure Fluctuations ◽  
Primary Source ◽  
Internal Flow ◽  
Rotational Frequency ◽  
High Flow ◽  
High Flow Rate ◽  
Centrifugal Pumps ◽  
Blade Passing Frequency

Double-suction centrifugal pumps are widely employed in large-scale pumping stations, which generally run in the conditions of large discharge with huge energy consumption. Pressure fluctuation caused by internal flow due to tongue-impeller interaction is the primary source of pump vibration. In this paper, pressure fluctuations and vibrations signals on volute casing wall were experimentally obtained at five flow rates ranging from 59% to 121% of nominal flow rate. Time and frequency domains of the signals were mainly analyzed by using statistical and fast Fourier transform methods. The results show that rotational frequency, blade passing frequency and their harmonic frequencies of pressure fluctuations as well as vibrations are clearly identified. The magnitude at blade passing frequency has close relationship with the measurement location related to the volute tongue, and becomes larger when the flow rate deviates from the nominal flow rate. The magnitudes at blade passing frequency can increase by 70% and 151% at high flow rate over that at the nominal flow rate for pressure fluctuations and vibrations, respectively. While the magnitude of vibration at rotational frequency keeps nearly constant at partial flow rate, and decreases at high flow rate.

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 0311 Study on Internal Flow of High Pressure-High Flow Rate Small-sized Cooling Fan

2012 ◽  
Vol 2012 (0) ◽  
pp. 147-148
Author(s):  
Takuya AGAWA ◽  
Junichiro FUKUTOMI ◽  
Toru SHIGEMITSU
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Internal Flow ◽  
High Flow ◽  
High Flow Rate ◽  
Cooling Fan

scholarly journals Effect of Air Injection on the Internal Flow Characteristics in the Draft Tube of a Francis Turbine Model

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1182
Author(s):  
Seung-Jun Kim ◽  
Yong Cho ◽  
Jin-Hyuk Kim
Keyword(s):  
Flow Rate ◽  
Draft Tube ◽  
Pressure Fluctuations ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Air Injection ◽  
Low Flow ◽  
Francis Turbine ◽  
Navier Stokes ◽  
Vortex Rope

Under low flow-rate conditions, a Francis turbine exhibits precession of a vortex rope with pressure fluctuations in the draft tube. These undesirable flow phenomena can lead to deterioration of the turbine performance as manifested by torque and power output fluctuations. In order to suppress the rope with precession and a swirl component in the tube, the use of anti-swirl fins was investigated in a previous study. However, vortex rope generation still occurred near the cone of the tube. In this study, unsteady-state Reynolds-averaged Navier–Stokes analyses were conducted with a scale-adaptive simulation shear stress transport turbulence model. This model was used to observe the effects of the injection in the draft tube on the unsteady internal flow and pressure phenomena considering both active and passive suppression methods. The air injection affected the generation and suppression of the vortex rope and swirl component depending on the flow rate of the air. In addition, an injection level of 0.5%Q led to a reduction in the maximum unsteady pressure characteristics.

scholarly journals Optimal Design of Slit Impeller for Low Specific Speed Centrifugal Pump Based on Orthogonal Test

2021 ◽  
Vol 9 (2) ◽  
pp. 121
Author(s):  
Yang Yang ◽  
Ling Zhou ◽  
Hongtao Zhou ◽  
Wanning Lv ◽  
Jian Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Large Scale ◽  
Internal Flow ◽  
Orthogonal Test ◽  
Centrifugal Pumps ◽  
Initial Model ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Four Levels

Marine centrifugal pumps are mostly used on board ship, for transferring liquid from one point to another. Based on the combination of orthogonal testing and numerical simulation, this paper optimizes the structure of a drainage trough for a typical low-specific speed centrifugal pump, determines the priority of the various geometric factors of the drainage trough on the pump performance, and obtains the optimal impeller drainage trough scheme. The influence of drainage tank structure on the internal flow of a low-specific speed centrifugal pump is also analyzed. First, based on the experimental validation of the initial model, it is determined that the numerical simulation method used in this paper is highly accurate in predicting the performance of low-specific speed centrifugal pumps. Secondly, based on the three factors and four levels of the impeller drainage trough in the orthogonal test, the orthogonal test plan is determined and the orthogonal test results are analyzed. This work found that slit diameter and slit width have a large impact on the performance of low-specific speed centrifugal pumps, while long and short vane lap lengths have less impact. Finally, we compared the internal flow distribution between the initial model and the optimized model, and found that the slit structure could effectively reduce the pressure difference between the suction side and the pressure side of the blade. By weakening the large-scale vortex in the flow path and reducing the hydraulic losses, the drainage trough impellers obtained based on orthogonal tests can significantly improve the hydraulic efficiency of low-specific speed centrifugal pumps.

scholarly journals The Enhancement of Pre-Storage Filtration Efficiency for the Rainwater Harvesting System in Malaysia

2018 ◽  
Vol 152 ◽  
pp. 02015
Author(s):  
Yoong Sion Ong ◽  
Ken Sim Ong ◽  
Y.k. Tan ◽  
Azadeh Ghadimi
Keyword(s):  
Stainless Steel ◽  
Flow Rate ◽  
Rainwater Harvesting ◽  
Filtration Efficiency ◽  
High Flow ◽  
High Flow Rate ◽  
Water Tank ◽  
Filtration System ◽  
Filter Screen ◽  
Water Piping

A conventional design of rainwater harvesting system collects and directs the rainwater through water piping from roof of building to the water storage. The filtration system which locates before the water tank storage and first flush bypass system is the main focus of the research. A filtration system consists of a control volume of filter compartment, filter screen (stainless steel mesh) and water piping that direct the water flow. The filtration efficiency of an existing filter “3P Volume Filter VF1” by industrial company is enhanced. A full scale filter design prototype with filter screen of 1000 μm stainless steel metal mesh is tested to compare with the original filter system design. Three types of water inlet setups are tested. Among the proposed water inlet setups, the 90° inlet setup with extension provides the best filtration rate per unit time, following by the 45° inlet setup. The 45° and 90° inlet setup has similar filtration efficiency at low to medium flow rate while 45° inlet setup has better efficiency at high flow rate. The filtration efficiency with the 90° inlet setup with extension is observed to maintain at highest value at medium to high flow rate. The overall filtration performance achieved by the 90° inlet setup with extension at low to high flow rate is between 34.1 to 35.7%.

Confirmation of high flow rate chaos in the Belousov-Zhabotinskii reaction

1992 ◽  
Vol 96 (3) ◽  
pp. 1228-1233 ◽  
Author(s):  
Laszlo Gyorgyi ◽  
Richard J. Field ◽  
Zoltan Noszticzius ◽  
William D. McCormick ◽  
Harry L. Swinney
Keyword(s):  
Flow Rate ◽  
High Flow ◽  
High Flow Rate ◽  
Belousov Zhabotinskii Reaction

High-flow rate miniature digital valve system

2017 ◽  
Vol 18 (3) ◽  
pp. 188-195 ◽  
Author(s):  
Tapio Lantela ◽  
Matti Pietola
Keyword(s):  
Flow Rate ◽  
High Flow ◽  
High Flow Rate ◽  
Valve System
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