Compendious Review on “Internal Flow Physics and Minimization of Flow Instabilities Through Design Modifications in a Centrifugal Pump”

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Neeta A. Mandhare ◽  
K. Karunamurthy ◽  
Saleel Ismail
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuations ◽  
Internal Flow ◽  
Boundary Layer Separation ◽  
Industrial Applications ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Design Modification ◽  
Flow Physics ◽  
And Performance

Centrifugal pumps are one of the significant consumers of electricity and are one of the most commonly encountered rotodynamic machines in domestic and industrial applications. Centrifugal pumps operating at off-design conditions are often subject to different periodic flow randomness, which in turn hampers functionality and performance of the pump. These limitations can be overcome by modification in the conventional design of different components of a centrifugal pump, which can assuage flow randomness and instabilities, reconstitute flow pattern and minimize hydraulic flow losses. In this article, flow vulnerabilities like pressure and flow inconsistency, recirculation, boundary layer separation, adverse rotor–stator interaction, and the effects on operation and performance of a centrifugal pump are reviewed. This article also aims to review design modification attempts made by different researchers such as impeller trimming, rounding, geometry modification of different components, providing microgrooves on the impeller and others. Based on the findings of this study, it is concluded that some design modifications of the impeller, diffuser, and casing result in improvement of functionality, efficiency, and reduction in pressure fluctuations, flow recirculation, and vibrations. Design modifications should improve the performance without hampering functionality and useful operational range of the pump. Considerable research is still necessary to continue understanding and correlating flow physics and design modifications for the pump impeller, diffuser, and casing.

scholarly journals Effect of Rotation Speed and Flow Rate on Slip Factor in a Centrifugal Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Bo Chen ◽  
Baolin Song ◽  
Bicheng Tu ◽  
Yiming Zhang ◽  
Xiaojun Li ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Rotation Speed ◽  
Internal Flow ◽  
Load Flow ◽  
Optical Measurements ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Slip Factor ◽  
Deviation Coefficient

This work analyzes the causes of the slip phenomenon in the impeller on the basis of the internal flow mechanism. Detailed optical measurements of the flow inside the rotation passages of a five-bladed centrifugal pump impeller are obtained through particle image velocimetry (PIV). On the basis of experimental data, the deviation coefficient of slip velocity is proposed and then revised according to the slip factor calculation formula of Stechkin. Results show that, at the same rotation speed, the slip factor increases with the flow rate and reaches the maximum value at 1.0 QBEP flow rate. At different rotation speeds, the slip factor increases with the rotation speed and shows a relatively large variation range. Moreover, a revised slip factor formula is proposed. The modified model is suitable for the correction of slip factor at part-load flow rates and serves as a guide for the hydraulic performance design and prediction of centrifugal pumps.

A dynamic simplified Lund model for large-eddy simulation and its application to a centrifugal pump

2018 ◽  
Vol 35 (7) ◽  
pp. 2577-2588 ◽  
Author(s):  
Xianbei Huang ◽  
Baoyun Qiu ◽  
Qiang Guo ◽  
Zhuqing Liu ◽  
Wei Yang ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Flow Structure ◽  
Numerical Stability ◽  
Large Scale ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Content Type ◽  
New Model ◽  
Non Linear

Purpose Construct a new sub-grid scale (SGS) model which can improve the efficiency and maintain comparative accuracy comparing to the existing dynamic cubic non-linear SGS model (DCNM). Design/methodology/approach The polynomial constitutive relation between the SGS stress tensor and both strain and rotation rate is selected as a basement. Simplification is achieved by eliminating the solid-body rotation term and adopting the assumption proposed by Kosovic. A dynamic procedure is applied to calculate three model coefficients in the new model. The new model (named dynamic simplified Lund model) and DCNM are applied to the rotating channel flow and the internal flow in a centrifugal pump impeller to examine the performance. Findings The new model is as accurate as DCNM but decreases 25 per cent computational resources. The ability of capturing rotation effect and reflecting backscatter is verified through cases. In addition, good numerical stability is shown during the calculation. Research limitations/implications More benchmark and engineering cases should be used to get further confidence on the new model. Practical implications The new model is promising in industrial application with the advantage of both accuracy and efficiency. For the flow with large-scale separation or more complicate phenomenon, the model is thought to give accurate flow structure. Originality/value A new non-linear SGS model is proposed in this paper. The accuracy, numerical stability and efficiency are validated for this model. Therefore, it is promising in the prediction of the flow structure in centrifugal pumps.

scholarly journals Influence of wall roughness on cavitation performance of centrifugal pump

2021 ◽  
Vol 43 (6) ◽  
Author(s):  
Weihui Xu ◽  
Xiaoke He ◽  
Xiao Hou ◽  
Zhihao Huang ◽  
Weishu Wang
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Internal Flow ◽  
Wall Roughness ◽  
Blade Surface ◽  
Centrifugal Pumps ◽  
Three Dimensional Model ◽  
Cavitation Inception ◽  
Cavitation Performance ◽  
Critical Cavitation

AbstractCavitation is a phenomenon that occurs easily during rotation of fluid machinery and can decrease the performance of a pump, thereby resulting in damage to flow passage components. To study the influence of wall roughness on the cavitation performance of a centrifugal pump, a three-dimensional model of internal flow field of a centrifugal pump was constructed and a numerical simulation of cavitation in the flow field was conducted with ANSYS CFX software based on the Reynolds normalization group k-epsilon turbulence model and Zwart cavitation model. The cavitation can be further divided into four stages: cavitation inception, cavitation development, critical cavitation, and fracture cavitation. Influencing laws of wall roughness of the blade surface on the cavitation performance of a centrifugal pump were analyzed. Research results demonstrate that in the design process of centrifugal pumps, decreasing the wall roughness appropriately during the cavitation development and critical cavitation is important to effectively improve the cavitation performance of pumps. Moreover, a number of nucleation sites on the blade surface increase with the increase in wall roughness, thereby expanding the low-pressure area of the blade. Research conclusions can provide theoretical references to improve cavitation performance and optimize the structural design of the pump.

scholarly journals Design and Optimization of a Centrifugal Pump for Slurry Transport Using the Response Surface Method

Machines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 60
Author(s):  
Khaled Alawadhi ◽  
Bashar Alzuwayer ◽  
Tareq Ali Mohammad ◽  
Mohammad H. Buhemdi
Keyword(s):  
Response Surface ◽  
Centrifugal Pump ◽  
Industrial Applications ◽  
Pump Efficiency ◽  
Optimized Design ◽  
Centrifugal Pumps ◽  
Local Pressure ◽  
Design And Optimization ◽  
Geometry Characteristic ◽  
Line Design

Since centrifugal pumps consume a mammoth amount of energy in various industrial applications, their design and optimization are highly relevant to saving maximum energy and increasing the system’s efficiency. In the current investigation, a centrifugal pump has been designed and optimized. The study has been carried out for the specific application of transportation of slurry at a flow rate of 120 m3/hr to a head of 20 m. For the optimization process, a multi-objective genetic algorithm (MOGA) and response surface methodology (RSM) have been employed. The process is based on the mean line design of the pump. It utilizes six geometric parameters as design variables, i.e., number of vanes, inlet beta shroud, exit beta shroud, hub inlet blade draft, Rake angle, and the impeller’s rotational speed. The objective functions employed are pump power, hydraulic efficiency, volumetric efficiency, and pump efficiency. In this reference, five different software packages, i.e., ANSYS Vista, ANSYS DesignModeler, response surface optimization software, and ANSYS CFX, were coupled to achieve the optimized design of the pump geometry. Characteristic maps were generated using simulations conducted for 45 points. Additionally, erosion rate was predicted using 3-D numerical simulations under various conditions. Finally, the transient behavior of the pump, being the highlight of the study, was evaluated. Results suggest that the maximum fluctuation in the local pressure and stresses on the cases correspond to a phase angle of 0°–30° of the casing that in turn corresponds to the maximum erosion rates in the region.

scholarly journals Analysis of the Influence of Different Bionic Structures on the Noise Reduction Performance of the Centrifugal Pump

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 886
Author(s):  
Cui Dai ◽  
Chao Guo ◽  
Yiping Chen ◽  
Liang Dong ◽  
Houlin Liu
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Centrifugal Pump ◽  
Great Influence ◽  
Frequency Doubling ◽  
Sound Field ◽  
Internal Flow ◽  
Test System ◽  
Centrifugal Pumps ◽  
External Characteristics

The strong noise generated during the operation of the centrifugal pump harms the pump group and people. In order to decrease the noise of the centrifugal pump, a specific speed of 117.3 of the centrifugal pump is chosen as a research object. The bionic modification of centrifugal pump blades is carried out to explore the influence of different bionic structures on the noise reduction performance of centrifugal pumps. The internal flow field and internal sound field of bionic blades are studied by numerical calculation and test methods. The test is carried out on a closed pump test platform which includes external characteristics and a flow noise test system. The effects of two different bionic structures on the external characteristics, acoustic amplitude–frequency characteristics and flow field structure of a centrifugal pump, are analyzed. The results show that the pit structure has little influence on the external characteristic parameters, while the sawtooth structure has a relatively great influence. The noise reduction effect of the pit structure is aimed at the wide-band noise, while the sawtooth structure is aimed at the discrete noise of the blade-passing frequency (BPF) and its frequency doubling. The noise reduction ability of the sawtooth structure is not suitable for high-frequency bands.

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.

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 Analysis and control of flow at suction connection in high-speed centrifugal pump

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668529 ◽  
Author(s):  
Wen-wu Song ◽  
Li-chao Wei ◽  
Jie Fu ◽  
Jian-wei Shi ◽  
Xiu-xin Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Internal Flow ◽  
Orifice Plate ◽  
Centrifugal Pumps ◽  
Pressure Area ◽  
Negative Effect ◽  
And Control ◽  
Experimental Data Analysis

The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.

scholarly journals Modelling and Rapid Prototyping of Centrifugal Pump Impeller Based on UG

2019 ◽  
Vol 291 ◽  
pp. 02009
Author(s):  
Yongmei Jiang ◽  
Zilong Wang ◽  
Zhao Jingnan
Keyword(s):  
Rapid Prototyping ◽  
Centrifugal Pump ◽  
3D Model ◽  
Pump Impeller ◽  
Innovative Design ◽  
Design Modification ◽  
Nurbs Curve ◽  
Curve Interpolation ◽  
Centrifugal Pump Impeller

The 3D model of centrifugal pump impeller in Unigraphics (UG) was optimized by implementing the principles of NURBS curve interpolation. The impeller was then manufactured by rapid prototyping equipment using polystyrene. The technique improves the efficiency in innovative design, modification, and fabrication.

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