Special Issue "State-of the-Art, Challenges and Perspectives in Hydraulic Machines and Systems"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "State-of-the-Art Energy Related Technologies".

Deadline for manuscript submissions: 31 March 2021.

Special Issue Editors

Dr. Sebastian Muntean
Website
Guest Editor
Center for Fundamental and Advanced Technical Research, Romanian Academy - Timisoara Branch, Bv. Mihai Viteazul, no. 24, Ro-300223 Timisoara, Romania
Interests: computational fluid dynamics; experimental investigations; hydrodynamics and cavitation in hydraulic machinery; swirling flow control
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Prof. Dr. Pavel Rudolf
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Guest Editor
Viktor Kaplan Department of Fluid Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, Brno, 616 69, Czech Republic
Interests: hydraulic machines; cavitation; swirling flows; shape optimization; CFD; flow control; fluid–structure interaction
Prof. Dr. Giovanna Cavazzini
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Guest Editor
Department of Industrial Engineering, University of Padova, Padua, Italy
Interests: hydraulic machines; unstable behavior; CFD; design optimization; experimental investigation
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Dr. Eduard Doujak
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Guest Editor
Fluid-Flow-Machinery Research Group, Institute for Energy Systems and Thermodynamics, TU Wien, Getreidemarkt 9/302, 1060 Vienna, Austria
Interests: design and optimization of components in hydraulic machinery; multistage pump-turbines for high head applications; lifetime assessment
Prof. Dr. Pål-Tore Selbo Storli
Website
Guest Editor
Waterpower Laboratory, Department of Energy and Process Engineering, Faculty of Engineering Sciences, Norwegian University of Science and Technology, Høgskoleringen 1, NO-7491 Trondheim, Norway
Interests: fluid–structure interactions in hydraulic turbines; system dynamics and generation flexibility

Special Issue Information

Dear Colleagues,

Modern hydraulic machines and systems are now facing new challenges associated with the variable demand on the energy market as well as limited energy storage capabilities. A great flexibility is required in operation over an extended range of regimes far from the best efficiency point. As a result, unsteady and transient phenomena occur in the operation of hydraulic machines and systems, diminishing their lifetime. The research topics in this Special Issue focus on: (i) the theoretical, numerical, and experimental investigations associated to the unsteady and transient phenomena developed in hydraulic machines, equipment, and systems, (ii) single-, two-, and multiphase phenomena in hydraulic machines and systems, (iii) innovative technologies and new concepts in hydraulic machines and systems to assess and to extend their lifetime, and (iv) passive, semiactive, and active control techniques applied to hydraulic machines to improve their performances.

Dr. Sebastian Muntean
Prof. Dr. Pavel Rudolf
Prof. Dr. Giovanna Cavazzini
Dr. Eduard Doujak
Prof. Dr. Pål-Tore Selbo Storli
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 papers will be 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. Energies 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 2000 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

  • Theoretical, numerical and experimental investigations in hydraulic machines, equipment, and systems
  • Unsteady and transients phenomena in operation
  • Single-, two-, and multiphase phenomena in hydraulic machines and systems
  • Innovative technologies and new concepts in hydraulic machines and systems
  • Lifetime time assessment of the hydraulic machines and equipment
  • Innovative technologies and new concepts in hydraulic machines and systems
  • Passive, semiactive, and active control techniques in hydraulic machines

Published Papers (3 papers)

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Research

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Open AccessArticle
A Tandem Axial-Piston Unit Based Strategy for the Reduction of Noise Sources in Hydraulic Systems
Energies 2020, 13(20), 5377; https://doi.org/10.3390/en13205377 - 15 Oct 2020
Abstract
This article presents a novel passive fluid borne noise source reduction strategy, based on tandem axial-piston unit indexing with the usage of symmetric lines. The strategy consists of setting the phase between the two synchronous units to accomplish destructive interference in targeted unit [...] Read more.
This article presents a novel passive fluid borne noise source reduction strategy, based on tandem axial-piston unit indexing with the usage of symmetric lines. The strategy consists of setting the phase between the two synchronous units to accomplish destructive interference in targeted unit harmonics. A strategy capable of achieving destructive interference in all odd harmonics is investigated first analytically and then confirmed by a simulation study. Experiments on the proposed strategy confirmed its effectiveness at the first and third pump fundamental harmonics, and pressure ripple reduction was accomplished. The fluid borne noise source reduction in the first and third harmonic is verified to be propagated to pipe vibration and sound power. Regarding the first harmonic, pressure ripple was reduced by up to 18 dB; while for third harmonic, pressure ripple was reduced by up to 11 dB. In the experiment, however, noise cancellation is not achieved for the higher odd harmonics, as is instead found in the simulation. Conversely, transfer functions form pressure ripple to pipe wall acceleration are obtained experimentally, and a critical vibration band from 2000 Hz to 3000 Hz is identified as being crucial for effective overall sound power reduction. Full article
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Open AccessFeature PaperArticle
Numerical Simulation of the Flow in a Kaplan Turbine Model during Transient Operation from the Best Efficiency Point to Part Load
Energies 2020, 13(12), 3129; https://doi.org/10.3390/en13123129 - 16 Jun 2020
Abstract
The aim of this study is to develop a reliable numerical model that provides additional information to experimental measurements and contributes to a better exploitation of hydraulic turbines during transient operation. The paper presents a numerical analysis of the flow inside a Kaplan [...] Read more.
The aim of this study is to develop a reliable numerical model that provides additional information to experimental measurements and contributes to a better exploitation of hydraulic turbines during transient operation. The paper presents a numerical analysis of the flow inside a Kaplan turbine model operated at a fixed runner blade angle during load variation from the best efficiency point (BEP) to part load (PL) operation. A mesh displacement is defined in order to model the closure of the guide vanes. Two different types of inlet boundary conditions are tested for the transient numerical simulations: linear flow rate variation (InletFlow) and constant total pressure (InletTotalPressure). A time step analysis is performed and the influence of the time discretization over the fluctuating quantities is discussed. Velocity measurements at the corresponding operating points are available to validate the simulation. Spectrogram plots of the pressure signals show the times of appearance of the plunging and rotating modes of the rotating vortex rope (RVR) and the stagnation region developed around the centerline of the draft tube is captured. Full article
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Review

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Open AccessReview
Flow Inside the Sidewall Gaps of Hydraulic Machines: A Review
Energies 2020, 13(24), 6617; https://doi.org/10.3390/en13246617 - 15 Dec 2020
Abstract
The paper critically reviews the current state of the art in flow inside sidewall gaps of hydraulic pumps and turbines. It describes the consequences of the presence of this type of flow in turbomachinery and then relates it to other physical phenomena that [...] Read more.
The paper critically reviews the current state of the art in flow inside sidewall gaps of hydraulic pumps and turbines. It describes the consequences of the presence of this type of flow in turbomachinery and then relates it to other physical phenomena that determine the behavior, operating characteristics, and overall performance of the machine. Despite the small dimensions of the rotor-stator spaces, the flow in these regions can significantly affect the overall flow field and, consequently, efficiency. The circulation of the fluid inside the gaps and secondary flow that is caused by rotating elements influences the disk friction losses, which is of great importance, especially in the case of low specific speed pumps and turbines. The flow pattern affects the pressure distribution inside a machine and, thus, generates axial thrust. The presence of secondary flow also significantly changes the rotordynamics and can bring about undesirable vibrations and acoustics issues. This article aims to review and summarize the studies that were conducted on the mentioned phenomena. Experimental and numerical studies are both taken into consideration. It proposes some requirements for prospective research in order to fill current gaps in the literature and reveals the upcoming challenges in the design of hydraulic machines. Full article
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