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Design and Optimization of Fluid Machinery, 2nd Edition
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Design and Optimization of Fluid Machinery, 2nd Edition

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydraulics and Hydrodynamics".

Deadline for manuscript submissions: 25 November 2024 | Viewed by 8191

Special Issue Editors

Dr. Leilei Ji

E-Mail Website
Guest Editor
National Research Center for Pumps and Systems, Jiangsu University, Zhenjiang, China
Interests: fluid machinery design and optimization; computational fluid dynamics (CFD); cavitation of pump; rotating stall of mixed-flow pump; transient characteristics during the startup period; PIV measurement
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Ramesh Agarwal

E-Mail Website
Guest Editor
Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
Interests: CFD; reactive flows; combustion; chemical looping; carbon capture and sequestration
Special Issues, Collections and Topics in MDPI journals
Dr. Yang Yang

E-Mail Website
Guest Editor
College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, China
Interests: hydraulic model; computational fluid dynamics (CFD); electric submersible pump (ESP); unstable flow; pressure pulsation; energy characteristics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Fluid machinery refers to fluid as the working medium for energy conversion machinery, including turbines, pumps, and compressors. Due to the wide application range, diverse applicable environment, and complex structure of fluid machinery, it is difficult to meet the changeable operating conditions through a fixed structure. Therefore, to maximize the structural performance of fluid machinery, it is necessary to optimize the structural parameters of fluid machinery on the basis of fully understanding the internal flow law of fluid machinery, so as to meet the development requirements of wide range, high efficiency, and energy saving in the current fluid machinery industry.

In recent years, with the emergence of artificial intelligence, machine learning, and various advanced optimization algorithms, the design and optimization of fluid machinery has re-emerged in the research community. In particular, with the help of CFD technology, people can observe the abnormal flow phenomenon in fluid machinery more intuitively and achieve rapid design and automatic optimization of fluid machinery structures by setting different optimization objectives.

This Special Issue seeks high-quality original research focusing on the latest novel advances regarding the design and optimization of fluid machinery. Original research and review articles are welcome.

Potential topics include but are not limited to the following:

  • Design and optimization of fluid machinery;
  • Cavitation performance and its control;
  • Numerical simulation of transient flow and instabilities;
  • Flow-induced vibration in fluid machinery;
  • Advanced optimization algorithm;
  • Application of artificial intelligence and machine learning in optimization;
  • Innovative technologies for flow control;
  • Suppression of unsteady flow.

Dr. Leilei Ji
Prof. Dr. Ramesh Agarwal
Dr. Yang Yang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • CFD
  • fluid machinery
  • design and optimization
  • shock and vibration
  • unsteady flow
  • cavitation
  • rotor dynamics

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Published Papers (11 papers)

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Research

20 pages, 10019 KiB  
Article
Computational Fluid Dynamics–Discrete Element Method Numerical Investigation of Binary Particle Mixing in Gas–Solid Fluidized Bed with Different Drag Models
by Chen Han, Xiaoling Fu, Xiaolu Guo, Wei Lu, Shaoqing Zhang, Hui Wang and Yang Yang
Water 2024, 16(22), 3210; https://doi.org/10.3390/w16223210 - 8 Nov 2024
Viewed by 397
Abstract
The fluidized bed is a critical reactor in the energy and chemical industries, where the mixing and agglomeration behaviors of binary particles significantly influence both the efficiency of reaction processes and the uniformity of final products. However, the selection of appropriate drag force [...] Read more.
The fluidized bed is a critical reactor in the energy and chemical industries, where the mixing and agglomeration behaviors of binary particles significantly influence both the efficiency of reaction processes and the uniformity of final products. However, the selection of appropriate drag force models remains a subject of debate due to the variability in particle properties and operating conditions. In this study, we investigated the fluidization behavior of binary mixtures composed of two different sizes of Geldart-D particles within a fluidized bed, evaluating nine distinct drag force models, including Wen and Yu; Schiller and Naumann; Ergun; Gidaspow, Bezburuah, and Ding; Huilin and Gidaspow; De Felice; Syamlal and O’Brien; and Hill, Koch, and Ladd. We focused on four key parameters: particle mixing degree, migration characteristics, temperature variation, and mean pressure drop. Simulation results revealed that the choice of drag model markedly affected mixing behavior, migration dynamics, and temperature distribution. Notably, the Ergun; Gidaspow, Bezburuah, and Ding; and Hill, Koch, and Ladd models exhibited superior particle mixing uniformity. While the drag model had a relatively minor impact on particle temperature changes, its selection became critical in simulations requiring high-temperature precision. Regarding pressure drop, the Huilin and Gidaspow and Gidaspow, Bezburuah, and Ding models demonstrated smaller and more stable pressure drop fluctuations. These findings offer valuable theoretical insights into gas–solid two-phase flow under binary particle mixing and provide practical guidance for the design and operation of fluidized bed reactors. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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32 pages, 34014 KiB  
Article
A Novel Modular Suspended Underwater Dredging Robot with a Suction and Jet-of-Pump Combination
by Xiangsheng Deng, Jianbin Luo and Cuilin Pan
Water 2024, 16(22), 3185; https://doi.org/10.3390/w16223185 - 7 Nov 2024
Viewed by 547
Abstract
This article introduces a novel modular suspended underwater dredging robot used for the biochemical reaction tanks of underground water treatment plants. The presented underwater robot can be used to perform dredging operations without touching underwater bottom facilities. The approach achieved a suction and [...] Read more.
This article introduces a novel modular suspended underwater dredging robot used for the biochemical reaction tanks of underground water treatment plants. The presented underwater robot can be used to perform dredging operations without touching underwater bottom facilities. The approach achieved a suction and jet-of-pump combination. This requires the underwater robot system to maintain a stable operation attitude in turbulent water flow which is generated by the pump. The study involves the overall design of underwater robots coordinated with the dredging module and details the development of a ground control platform and underwater sensing sonar system. Depending on the location of the dredging, the robot has two operation modes: suspended mode and bottom sitting mode. The experimental results validate the feasibility and effectiveness of the underwater dredging robot. This research can achieve dredging in biochemical reaction tanks without interrupting operations and facilitates the development of intelligent operations in the water treatment industry. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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21 pages, 17363 KiB  
Article
Analysis of Flow Loss Characteristics of a Multistage Pump Based on Entropy Production
by Qi Meng, Guidong Li, Jieyun Mao, Danhua Zhao, Yutong Luo and Tengfei Hou
Water 2024, 16(20), 2974; https://doi.org/10.3390/w16202974 - 18 Oct 2024
Viewed by 474
Abstract
To reveal the internal flow loss characteristics of a multi-stage pump, the unsteady calculation of the internal flow field of a seven-stage centrifugal pump was carried out, and the entropy production theory and Q criterion were utilized to analyze the unsteady flow characteristics [...] Read more.
To reveal the internal flow loss characteristics of a multi-stage pump, the unsteady calculation of the internal flow field of a seven-stage centrifugal pump was carried out, and the entropy production theory and Q criterion were utilized to analyze the unsteady flow characteristics of each flow component under different flow rates. The research results show that as the flow rate increases, the entropy production value and the energy loss inside the flow components also increase accordingly. The viscous dissipation entropy production caused by fluid viscosity is very small, and the turbulent dissipation entropy production caused by turbulent fluctuations and wall dissipation entropy production are the main sources of energy loss. The impellers, diffusers, and outlet chamber are the main regions of energy loss in the multistage pump. The entropy production value of the first-stage impeller is significantly higher than that of other impellers, while the entropy production value of the first-stage diffuser is significantly lower than that of other diffusers. Through vortex structure analysis, it is found that the high entropy production regions in the impeller are concentrated in the impeller inlet area, the blade suction surface, and the impeller outlet area. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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20 pages, 13098 KiB  
Article
Influence of Different Valve Openings on the Structural Dynamic Characteristics of a Multistage Pump
by Guidong Li, Yinling Xia, Jieyun Mao, Danhua Zhao and Qi Meng
Water 2024, 16(20), 2964; https://doi.org/10.3390/w16202964 - 17 Oct 2024
Viewed by 490
Abstract
In order to study the influence of regulating valve openings on the dynamic characteristics of the rotor structure of a multistage pump during the transient startup process, a seven-stage pump was selected as the research object. The transient startup of the pump was [...] Read more.
In order to study the influence of regulating valve openings on the dynamic characteristics of the rotor structure of a multistage pump during the transient startup process, a seven-stage pump was selected as the research object. The transient startup of the pump was jointly simulated using Flowmaster and CFX, and the deformation law of the rotor under different valve openings with time was investigated through Workbench. The results showed that the deformation trends of the impellers at each stage were similar under different valve openings during transient startup, and regulating the valve opening had little significant impact on the stability of the rotor structure. The maximum deformation of the pump shaft occurred at the contact surface between the intermediate impeller and the pump shaft under different valve openings. As the valve opening increased, the maximum deformation of the pump shaft decreased slightly. This study reveals the structural characteristics of the multistage pump during the transient startup process under different valve openings, which is of great importance for improving the safety and reliability of multistage pumps during emergency operations. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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19 pages, 6931 KiB  
Article
The Effect of Reynolds Numbers on Flow-Induced Vibrations: A Numerical Study of a Cylinder on Elastic Supports
by Chunhui Ma, Fenglai Huang, Bin Li, Xujian Li and Yu Liu
Water 2024, 16(19), 2765; https://doi.org/10.3390/w16192765 - 28 Sep 2024
Viewed by 864
Abstract
In the field of fluid dynamics, the Reynolds number is a key parameter that influences the flow characteristics around bluff bodies. While its impact on flow around stationary cylinders has been extensively studied, systematic research into flow-induced vibrations (FIVs) under these conditions remains [...] Read more.
In the field of fluid dynamics, the Reynolds number is a key parameter that influences the flow characteristics around bluff bodies. While its impact on flow around stationary cylinders has been extensively studied, systematic research into flow-induced vibrations (FIVs) under these conditions remains limited. This study utilizes numerical simulations to explore the FIV characteristics of smooth cylinders and passive turbulence control (PTC) cylinders supported elastically within a Reynolds number range from 0.8 × 104 to 1.1 × 105. By comparing the vibration responses, lift coefficients, and wake structures of these cylinders across various Reynolds numbers, this paper aims to elucidate how Reynolds numbers affect the flow and vibration characteristics of these structures. The research employs images of instantaneous lift changes and vortex shedding across multiple sections to visually demonstrate the dynamic changes in flow states. The findings are expected to provide theoretical support for optimizing structural design and vibration control strategies in high-Reynolds-number environments, emphasizing the importance of considering Reynolds numbers in structural safety and design optimization. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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16 pages, 6819 KiB  
Article
Analysis and Identification of Eccentricity of Axial-Flow Impeller by Variational Mode Decomposition
by Houyu Zhang, Yingbo Guan, Zilong Hu, Weilong Guang, Di Zhu, Ran Tao and Ruofu Xiao
Water 2024, 16(18), 2605; https://doi.org/10.3390/w16182605 - 14 Sep 2024
Viewed by 404
Abstract
The axial-flow impellers are widely applied to industry due to their excellent hydraulic performance and simple structure, but they may be affected by their eccentricity during operation. This study compared and studied the effects of the axial-flow eccentricity of an impeller on hydraulic [...] Read more.
The axial-flow impellers are widely applied to industry due to their excellent hydraulic performance and simple structure, but they may be affected by their eccentricity during operation. This study compared and studied the effects of the axial-flow eccentricity of an impeller on hydraulic performance, impeller radial force, and downstream pressure pulsation of the unit. The research results indicate that impeller eccentricity has a small effect on hydraulic performance. Compared with the design conditions, the efficiency, power, and head changes caused by impeller eccentricity are all less than 1%, but the impeller eccentricity leads to a sharp increase in the radial force of the impeller. Under the design conditions, the average value of the radial force of the impeller is 31.38 N; under eccentric conditions, the average value of the radial force of the impeller increased by nine times, reaching 316.30 N. By analyzing the pressure pulsation signals decomposed by the VMD method, it is shown that the influence of eccentricity on pressure pulsation is mainly reflected in the increase in impeller frequency on pressure pulsation. Under design conditions, the corresponding amplitude of the impeller frequency is 2.6; under eccentric conditions, the amplitude corresponding to the impeller frequency increased by 100 times, reaching 274.4. This study elucidates the specific effects of axial impeller eccentricity, providing theoretical guidance for the safe and stable operation of axial-flow units, and has important engineering significance. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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17 pages, 12527 KiB  
Article
Study on Part-Load Cavitation in High-Specific-Speed Centrifugal Pump
by Zhenhua Shen, Chao Wang, Jinfeng Zhang, Shijun Qiu and Rong Lin
Water 2024, 16(15), 2180; https://doi.org/10.3390/w16152180 - 1 Aug 2024
Cited by 1 | Viewed by 848
Abstract
Some high-specific-speed centrifugal pumps exhibit instability in terms of hydraulic performance and cavitation characteristics, and there’s a lack of reliable numerical models to guide the optimization of cavitation instability. This paper, by conducting a study on mesh independence, analyzes the cavitation curves and [...] Read more.
Some high-specific-speed centrifugal pumps exhibit instability in terms of hydraulic performance and cavitation characteristics, and there’s a lack of reliable numerical models to guide the optimization of cavitation instability. This paper, by conducting a study on mesh independence, analyzes the cavitation curves and cavitation counters for various mesh combinations in the numerical model, The findings indicate that the boundary layer grid not only influences the location of peak points but also the size of the peak. To achieve a stable NPSH peak position, the y+ at the blade leading edge of high-specific-speed centrifugal pumps needs to be controlled between 20–80. The turbulence model, evaporation coefficient, and condensation coefficient were simulated using the orthogonal experimental design method, analyzing the impact of these parameters on the NPSH peak. A visual high-speed photography test rig was established, and rotating cavitation and sheet cavitation is found at part-load. By comparing the cavitation and pressure counters with high-speed photography images, a numerical model was obtained that closely mirrors the experimental cavitation characteristics. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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18 pages, 16056 KiB  
Article
The Influence of Lobe Top Clearance on the Performance of High-Speed Centrifugal Pumps
by Dongxu Wang, Kai Wang, Ziqiang Wang, Dongwei Wu and Ying Song
Water 2024, 16(14), 1943; https://doi.org/10.3390/w16141943 - 10 Jul 2024
Viewed by 691
Abstract
High-speed centrifugal pumps are widely used in several industries due to their high efficiency and small footprint. In actual applications, there are issues such as low operational efficiency and a small high-efficiency flow interval; particularly, the leakage occurring in the impeller channel gap [...] Read more.
High-speed centrifugal pumps are widely used in several industries due to their high efficiency and small footprint. In actual applications, there are issues such as low operational efficiency and a small high-efficiency flow interval; particularly, the leakage occurring in the impeller channel gap presents a significant barrier to the pump’s performance and stability. This study takes the fully open impeller miniature high-speed centrifugal pump as the object and uses a numerical simulation calculation method. The objective of this research endeavor is to analyze the effects of different flow conditions on a high-speed centrifugal pump’s external characteristics, flow field characteristics, and energy loss. The findings indicate that lobe top clearance exerts a substantial impact on the efficiency of high-speed centrifugal pumps. Increasing the lobe top clearance will result in a reduction in pump head and efficiency, particularly under high flow conditions. The lobe top clearance has a significant impact on the complexity of the flow in the impeller, particularly the flow close to the suction surface of the impeller, according to an analysis of the flow field characteristics. The energy loss analysis further confirms the importance of reducing lobe top clearance for improving pump performance and reducing energy loss. These results provide valuable guidance for optimizing centrifugal pump designs with lobe top clearance. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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29 pages, 18680 KiB  
Article
Study on the Transient Flow Characteristics of Multistage Centrifugal Pumps during the Startup Process before System Operation
by Chao Chen, Hu Xu, Fanjie Deng, Kaipeng Wu, Zhen Zhang and Qiaorui Si
Water 2024, 16(13), 1876; https://doi.org/10.3390/w16131876 - 29 Jun 2024
Cited by 2 | Viewed by 1114
Abstract
Multistage pumps are essential in emergency water supply, irrigation, and other systems undergoing unavoidable hydraulic transitions like pump startup and valve operations. These transitions cause rapid changes in impeller speed, flow rate, and pressure, destabilizing the internal flow field and impacting system reliability. [...] Read more.
Multistage pumps are essential in emergency water supply, irrigation, and other systems undergoing unavoidable hydraulic transitions like pump startup and valve operations. These transitions cause rapid changes in impeller speed, flow rate, and pressure, destabilizing the internal flow field and impacting system reliability. To study transient flow characteristics, a numerical analysis of a three-stage pump was conducted, focusing on vortex identification, entropy production, and time–frequency pressure pulsation. Using the SST turbulence model, the simulation analyzed different start times and flow rate variations. Findings revealed that shorter startup times intensified transient effects, with the head increasing rapidly initially and then stabilizing. Vortex structures showed periodic development and dissipation. Entropy production rose with impeller speed, peaking higher with shorter startups. Blade passing frequency dominated pressure pulsations, with increased low-frequency pulsations as speed rose. During valve opening, flow stabilization accelerated with increasing flow rates, reducing amplitude and eliminating low-frequency components. This research aids the reliable operation of high-pressure pumping systems in energy storage. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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17 pages, 9233 KiB  
Article
Research on Internal Flow and Pressure Fluctuation Characteristics of Centrifugal Pumps as Turbines with Different Blade Wrap Angles
by Haibo Xu, Weizheng An, Erqinhu Ke, Yingyi Ma, Linlin Geng, Gang Yang and Desheng Zhang
Water 2024, 16(13), 1861; https://doi.org/10.3390/w16131861 - 28 Jun 2024
Viewed by 753
Abstract
The use of pumps as turbines has been gaining more and more attention in recent years. The present work mainly investigates the influence of blade wrap angle on the internal flow and pressure fluctuation characteristics of centrifugal pumps as turbines. Five different wrap [...] Read more.
The use of pumps as turbines has been gaining more and more attention in recent years. The present work mainly investigates the influence of blade wrap angle on the internal flow and pressure fluctuation characteristics of centrifugal pumps as turbines. Five different wrap angles (35°,45°, 55°, 65°, and 75°) for a forward-curved impeller were numerically analyzed under multiple operating conditions. The accuracy of numerical simulation was validated by experimental results. The results show that maximum efficiency is achieved with a blade wrap angle of 35°, and the highest efficiency flow point gradually decreases as the blade wrap angle increases. It is found by conducting entropy production theory analysis that the high-entropy production rate regions in PATs are concentrated in the volute tongue and impeller blade inlet regions, and that the entropy production rate at the impeller inlet region increases and then decreases as the blade wrap angle decreases. In addition, pressure pulsation was affected not only by dynamic and static interference but also by an irregular vortex around the impeller; its magnitude under Qt is higher than 0.8Qt for blade wrap angles of 55° and 75°. The primary frequency of pressure pulsation within the impeller is the axial frequency fn and its multiples, and the frequency with the largest amplitude is 3fn. The periodicity of vortices is closely related to the periodicity of pressure pulsation. And it is suggested that a PAT with a 35° blade wrap angle is advantageous for improving the stability of a turbine. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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19 pages, 7347 KiB  
Article
The Influence of Different Working Fluid Temperatures on the Hydraulic Performance of Magnetic Vortex Pumps
by Yijia Cheng, Wei Li, Sizhuo Ma, Leilei Ji, Cui Xiao and Yongkang Li
Water 2024, 16(11), 1601; https://doi.org/10.3390/w16111601 - 3 Jun 2024
Viewed by 739
Abstract
Magnetic vortex pumps are characterized by their high performance and zero leakage, and in recent years, they have been applied for the transportation of antifreeze coolant in varying-temperature environments. This paper combines Computational Fluid Dynamics (CFD) with experimental verification to study the external [...] Read more.
Magnetic vortex pumps are characterized by their high performance and zero leakage, and in recent years, they have been applied for the transportation of antifreeze coolant in varying-temperature environments. This paper combines Computational Fluid Dynamics (CFD) with experimental verification to study the external and internal flow characteristics of magnetic vortex pumps when transporting working fluid at different temperatures, considering radial clearance flow. The results indicate that as the temperature of the medium increases, both the pump head and efficiency improve. Specifically, under the design flow rate condition, the pump head increases by 16.7% when transporting a medium at 90 °C compared to ambient-temperature conditions. Conversely, the pump head is only 16.8% of that observed under ambient-temperature conditions when transporting a medium at −30 °C. Analysis of the internal flow field reveals that the changes in pump hydraulic performance at different working fluid temperatures are primarily due to variations in the vorticity of the internal flow field. Full article
(This article belongs to the Special Issue Design and Optimization of Fluid Machinery, 2nd Edition)
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