Now showing items 1-20 of 27

  • Additional effects of uid on the piston 

    Himr, Daniel; Habán, Vladimír; Kůrečka, Jan; Pochylý, František (EDP Sciences, 2018-06-04)
    Additional eect of uid on the solid body is often ignored phenomenon. Although it is possible to do an analytic derivation of equations describing additional eects for many various conditions, it can be dicult to solve ...
  • Aeration equipment for small depths 

    Sluše, Jan; Pochylý, František (EDP Sciences, 2015-05-06)
    Deficit of air in water causes complications with cyanobacteria mainly in the summer months. Cyanobacteria is a bacteria that produces poison called cyanotoxin. When the concentration of cyanobacteria increases, the phenomena ...
  • Analytical Formula for the Mean Velocity Profile in a Pipe Derived on the Basis of a Spatial Polynomial Vorticity Distribution 

    Štigler, Jaroslav (MDPI, 2021-05-14)
    The derivation of the mean velocity profile for a given vorticity distribution over the pipe cross-section is presented in this paper1. The velocity profile and the vorticity distribution are axisymmetric, which means that ...
  • Application of Computer Graphics Flow Visualization Methods in Vortex Rope Investigations 

    Urban, Ondřej; Kurková, Michaela; Rudolf, Pavel (MDPI, 2021-01-26)
    Computer graphics visualization techniques for application on data from Computational Fluid Dynamics (CFD) simulations of the vortex rope, a phenomenon present in hydraulic turbines operating in off-design conditions, were ...
  • Check valve slam analysis in pumping station 

    Himr, Daniel; Habán, Vladimír; Dokoupil, Pavel (EDP Sciences, 2016-03-28)
    Pumping station supplies water for technological process. The check valve in the station was replaced with a new one. The regular test of black out discovered the high pressure pulsations accompanied with noticeable pipeline ...
  • Comprehensive Study Of Unsteady Pressure Pulsations Induced By The Spiral Vortex Structure In A Conical Diffuser 

    Štefan, David; Rudolf, Pavel; Hudec, Martin; Habán, Vladimír (Faculty of Technologies and Systems, 2015-09-09)
    The decelerated swirling flow often breaks down into helical structure which is unstable and causes unsteady velocity and pressure fields. The numerical and experimental investigation of this flow pattern is carried out ...
  • Design of a high-specific speed turbine with non-uniform blade cascade 

    Stareček, Jakub; Čupr, Pavel; Haluza, Miloslav (EDP Sciences, 2019-06-28)
    This paper presents the hydraulic design of Kaplan type turbine in fully axial configuration. The turbine model consists of a straight pipe intake, a rib which covers the shaft, five axial guide vanes, a six blade runner ...
  • Design of hydraulic recuperation unit 

    Jandourek, Pavel; Habán, Vladimír; Hudec, Martin; Dobšáková, Lenka; Štefan, David (EDP Sciences, 2015-11-17)
    Article deals with design and measurement of hydraulic recuperation unit. Recuperation unit consist of radial turbine and axial pump, which are coupled on the same shaft. Speed of shaft with impellers are 6000 1/min. For ...
  • Dynamics of pressure pulsations in thin annular gap 

    Kůrečka, Jan; Himr, Daniel; Habán, Vladimír (IOP Publishing, 2021-06-15)
    Fluid pulsations can significantly influence behavior of bearings or sealing parts of hydraulic machines and therefore their operation. In this contribution, an analytical approach to solve pressure pulsations dynamics is ...
  • Effect of Splitter Blades on Performances of a Very Low Specific Speed Pump 

    Chabannes, Lilian; Štefan, David; Rudolf, Pavel (MDPI, 2021-06-24)
    The usage of splitter blades to enhance the performances of low specific speed pumps is common practice. Based on experimental and numerical studies, the influence of the addition of one and two splitter blades is investigated ...
  • Experimental analysis of static and dynamic properties of the check valves 

    Dokoupil, Pavel; Himr, Daniel; Habán, Vladimír (EDP Sciences, 2019-06-28)
    The check valves play an important role in safety and reliability of many technologies using liquid or gas flow. Check valves are elements of the hydraulic system enabling the one-way flow without a significant pressure ...
  • Experimental investigation of check valve behaviour during the pump trip 

    Himr, Daniel; Habán, Vladimír; Hudec, Martin (IOP Publishing, 2017-04-04)
    The paper is focused on the description of an experimental investigation of a nozzle check valve. Attention is paid to the behaviour during transitions when the flow is decelerating. Flow reversal is often accompanied with ...
  • Experimental investigation of swirl number influence on spiral vortex structure dynamics 

    Štefan, David; Hudec, Martin; Uruba, Václav; procházka, pavel; Urban, Ondřej; Rudolf, Pavel (IOP Publishing, 2021-06-15)
    The hydraulic turbines are recently forced to operate far away from the optimal conditions in order to balance fluctuations in electricity generation. In case of Francis, pump and propeller turbines, using only single ...
  • Experimental investigation of the check valve behaviour when the flow is reversing 

    Himr, Daniel; Habán, Vladimír; Hudec, Martin; Pavlík, Václav (EDP Sciences, 2017-05-12)
    Check valve in a pipeline is supposed to prevent the reverse flow and to allow the flow in the positive direction. The construction of check valves follows these requirements, but the check valve must not cause pressure ...
  • Flow Inside the Sidewall Gaps of Hydraulic Machines: A Review 

    Zemanová, Lucie; Rudolf, Pavel (MDPI, 2020-12-15)
    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 ...
  • FSI Computation and Experimental Verification of Fluid Flow in Flexible Tubes 

    Šedivý, Dominik; Fialová, Simona; Klas, Roman; Kotek, Michal (Sciendo, 2020-07-24)
    Presented paper is focused on the experimental and computational study of fluid flow in pipes with flexible walls. One possible real example of this phenomenon is the blood flow in arteries or their substitutes in the human ...
  • Influence of Second Viscosity on Pressure Pulsation 

    Himr, Daniel; Habán, Vladimír; Fialová, Simona (MDPI, 2019-12-12)
    A mathematical model of pulsating flow is proposed in the paper. The model includes more accurate description of energy dissipation, so it allows, for example, better stability analysis of water power plant control and ...
  • Inner Damping of Water in Conduit of Hydraulic Power Plant 

    Himr, Daniel; Habán, Vladimír; Štefan, David (MDPI, 2021-06-25)
    The operation of any hydraulic power plant is accompanied by pressure pulsations that are caused by vortex rope under the runner, rotor–stator interaction and various transitions during changes in operating conditions or ...
  • An Investigation of Viscous Torque Loss in Ball Bearing Operating in Various Liquids 

    Dobrovolný, Martin; Habán, Vladimír; Tancjurová, Jana; Zbavitel, Jan (MDPI, 2021-05-08)
    The limited functionality of seals that are used in hydraulic machines to prevent the liquid from leaking into the bearings may result in decrease in machine efficiency and reliability and may cause an accident of the whole ...
  • Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection 

    Rudolf, Pavel; Litera, Jiří; Ibarra Bolanos, Germán Alejandro; Štefan, David (EDP Sciences, 2018-06-04)
    Vortex rope, which induces substantial pressure pulsations, arises in the draft tube (diffuser) of Francis turbine for off-design operating conditions. Present paper focuses on mitigation of those pulsations using active ...