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 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.

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.

Comparative study of SGS models for simulating the flow in a centrifugal-pump impeller using single passage

2015 ◽  
Vol 32 (7) ◽  
pp. 2120-2135 ◽  
Author(s):  
Xianbei Huang ◽  
Zhuqing Liu ◽  
Wei Yang
Keyword(s):  
Temporal Variation ◽  
Centrifugal Pump ◽  
Dynamic Models ◽  
Internal Flow ◽  
Smagorinsky Model ◽  
Pump Impeller ◽  
Content Type ◽  
Design Load ◽  
Model Coefficient ◽  
Centrifugal Pump Impeller

Purpose – The purpose of this paper is to bring in and clarify the performance of the Vreman and dynamic Vreman models (VM and DVM) in simulating the internal flow of the centrifugal pump impeller. Design/methodology/approach – Four subgrid scale (SGS) models, including the Smagorinsky model, the dynamic Smagorinsky model, the VM and the DVM are chosen to study the performance in predicting the flow field in the centrifugal pump impeller at design load. The velocity and turbulent kinetic energy distributions are compared. Also, the temporal variation of the model coefficient of the DVM is studied. Findings – The results of all the four models show agreement with both the PIV and LDV data. It is clarified that the VM and the DVM are adaptive in simulating the turbulent flow in the centrifugal pump at design load, and the DVM shows even better performance in predicting the velocity distribution. Additionally, the temporal variation of the model coefficient of the DVM is about 0.01, which is the optimal value for VM in this study. It is verified that VM can perform as good as the dynamic models when an appropriate model coefficient is chosen. Originality/value – The applicability of the VM and the DVM in simulating the internal flow of the centrifugal pump has been proven at design load. The introducing of the two models into centrifugal pump’s simulation can provide some new ideas in constructing more adaptive SGS models for this kind of high-rotating flow.

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 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 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.

Comparison of Inlet Curved Disk Arrangements for Suppression of Recirculation in Centrifugal Pump Impellers

2016 ◽  
Author(s):  
Munther Y. Hermez ◽  
Badih A. Jawad ◽  
Liping Liu ◽  
Vernon Fernandez ◽  
Kingman Yee ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Operating Cost ◽  
Three Dimensional ◽  
Centrifugal Pumps ◽  
Unstable Flow ◽  
Pump Impeller ◽  
Flow Rates ◽  
Flow Recirculation ◽  
Flow Field Characteristics

The present work aims to numerically study the inlet flow recirculation and modified impeller interaction in a centrifugal pump. An optimization of modified shrouded impeller with curved disk arrangement to suppress the unsteady flow recirculation is pursued. This modification will enhance the impeller characteristics with a wider operation range at both low and high flow rates in a high speed centrifugal pump type. The unstable flow in the centrifugal pumps is a common problem that leads to damage in the pump’s internal parts, consequently increases the operating cost. At certain flow rates, generally below the Best Efficiency Point (BEP), all centrifugal pumps are subject to internal recirculation occurs at the suction and discharge areas of the impeller. For decades, experimental work has been done to investigate the complex three-dimensional flow within centrifugal pumps impellers, before computational work gains momentum due to advancement of computing power and improved numerical codes. In this study the impeller with a curved disk arrangement has been investigated by using a three-dimensional Navier-Stokes code with a standard k-ε turbulence model. The purpose is to evaluate and select the optimum impeller modification that would increase the pump suction flow rate range. Three-dimensional numerical Computational Fluid Dynamics (CFD) tools are used to simulate flow field characteristics inside the centrifugal pump and provide critical hydraulic design information. In the present work, ANSYS v.16.1 Fluent solver is used to analyze the pressure and velocity distributions inside impeller suction and discharge passages. The ultimate goal of this study is to manufacture and validate the most optimized and efficient centrifugal pump impeller with a curved disk. The best case curve identifies the highest increase of total pressure difference by 22.1%, and highest efficiency by 92.3% at low flowrates.

The Rotating Cavitation Performance of a Centrifugal Pump with a Splitter-Bladed Inducer under Different Rotational Speed

2015 ◽  
Vol 32 (3) ◽  
Author(s):  
XiaoMei Guo ◽  
ZuChao Zhu ◽  
BaoLing Cui ◽  
Yi Li
Keyword(s):  
Centrifugal Pump ◽  
Rotational Speed ◽  
High Speed ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Cavitation Flow ◽  
Operation Condition ◽  
Cavitation Performance ◽  
Cavitation Behavior ◽  
Suction Performance

AbstractDesigning inducer is one of the effective ways to improve the suction performance of high-speed centrifugal pumps. The operation condition including rotational speeds can affect the internal flow and external performance of high-speed centrifugal pumps with an inducer. In order to clarify the rotating cavitation performance of a centrifugal pump with a splitter-bladed inducer under different rotational speed, a centrifugal pump with a splitter-bladed inducer is investigated in the work. By using Rayleigh–Plesset equations and Mixture model, the cavitation flow of centrifugal pump is numerically simulated, as well as the external performance experimental test is carried out. It is found that the cavitation area increases with the rotational speeds. The location of the passage where cavitation is easy to appear is explored. Asymmetric cavitation behavior is observed. That, the trail of the inducer is easy to take cavitation when the rotational speed is increased to a degree, is also observed. The trend of

scholarly journals Optimization and Analysis of Centrifugal Pump considering Fluid-Structure Interaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Zhang ◽  
Sanbao Hu ◽  
Yunqing Zhang ◽  
Liping Chen
Keyword(s):  
Centrifugal Pump ◽  
Fluid Structure Interaction ◽  
Kriging Model ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Transient Vibration ◽  
Pump Impeller ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Vibration Performance

This paper presents the optimization of vibrations of centrifugal pump considering fluid-structure interaction (FSI). A set of centrifugal pumps with various blade shapes were studied using FSI method, in order to investigate the transient vibration performance. The Kriging model, based on the results of the FSI simulations, was established to approximate the relationship between the geometrical parameters of pump impeller and the root mean square (RMS) values of the displacement response at the pump bearing block. Hence, multi-island genetic algorithm (MIGA) has been implemented to minimize the RMS value of the impeller displacement. A prototype of centrifugal pump has been manufactured and an experimental validation of the optimization results has been carried out. The comparison among results of Kriging surrogate model, FSI simulation, and experimental test showed a good consistency of the three approaches. Finally, the transient mechanical behavior of pump impeller has been investigated using FSI method based on the optimized geometry parameters of pump impeller.

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