• A New Technical Concept for Water Management and Possible Uses in Future Water Systems 

      Storli, Pål-Tore Selbo; Lundstrøm, T. Staffan (Journal article; Peer reviewed, 2019)
      A new degree of freedom in water management is presented here. This is obtained by displacing water, and in this paper is conceptually explained by two methods: using an excavated cavern as a container for compressed air ...
    • A test of the v 2-f k-epsilon turbulence model for the prediction of vortex shedding in the Francis-99 hydrofoil test case 

      Sagmo, Kristian Forfot; Storli, Pål-Tore Selbo (Journal article; Peer reviewed, 2019)
      A test of the v 2 − f k − epsilon turbulence model for the flow around the Francis-99 hydrofoil geometry is conducted in order to assess it's accuracy of trailing edge vortex shedding prediction. The model is based on the ...
    • Design of Groundwater Heat Pump Systems. Principles, Tools, and Strategies for Controlling Gas and Precipitation Problems 

      Gjengedal, Sondre; Stenvik, Lars Aaberg; Storli, Pål-Tore Selbo; Ramstad, Randi Kalskin; Hilmo, Bernt Olav; Frengstad, Bjørn S. (Journal article; Peer reviewed, 2019)
      The utilization of groundwater heat pump systems is increasing in Norway, which are currently widely employed for heating and cooling applications in the town center of Melhus. The investigations of the Melhus installations ...
    • Dynamic load on a Francis turbine runner from simulations based on measurements 

      Storli, Pål-Tore Selbo; Nielsen, Torbjørn Kristian (Journal article; Peer reviewed, 2014)
      The frequency of the Nordic power grid has become more volatile during recent years. This gives rise to two effects in synchronous machines. Firstly, as grid frequency changes the rotational speed of synchronous machines ...
    • Fast Transition between Operational Modes of a reversible Pump-Turbine 

      Svarstad, Magni Fjørtoft (Doctoral theses at NTNU;2019:49, Doctoral thesis, 2019)
      The future demands of energy production to balance more intermittent energy sources creates two main technical challenges for the hydro power production. Increased off-design operation, including both operation outside ...
    • Francis-99: Coupled simulation of the resonance effects in runner channels 

      Tengs, Erik Os; Fevåg, Live Salvesen; Storli, Pål-Tore Selbo (Journal article; Peer reviewed, 2019)
      A resonance phenomenon is observed experimentally in the runner channels of the Francis-99 model turbine runner. An incompressible CFD simulation is unable to simulate this. Two different coupled physics schemes are therefore ...
    • Measurements and simulations of turbines on common grid 

      Nielsen, Torbjørn Kristian; Storli, Pål-Tore Selbo (Journal article; Peer reviewed, 2014)
      Speed droop control is of basic importance for the primary governing in the Nordic grid. The speed droop control. a mandatory and build-in regulatory loop on all larger units. is automatically changing the produced power ...
    • Model Order Reduction Technique Applied on Harmonic Analysis of a Submerged Vibrating Blade 

      Tengs, Erik Os; Charrassier, Flora; Storli, Pål-Tore Selbo; Holst, Martin (Journal article; Peer reviewed, 2019)
      As part of an ongoing study into hydropower runner failure, a submerged, vibrating blade is investigated both experimentally and numerically. The numerical simulations performed are fully coupled acoustic-structural ...
    • Numerical Generation of Hill-Diagrams; Validation on the Francis99 Model Turbine 

      Tengs, Erik Os; Storli, Pål-Tore Selbo; Holst, Martin (Journal article; Peer reviewed, 2018)
      This article compares a numerically simulated, and an experimentally obtained Hill-Diagram. The Francis99 model turbine was used in the validation. By using steady-state simulations and passage modeling in ANSYS CFX, the ...
    • Optimization procedure for variable speed turbine design 

      Tengs, Erik Os; Storli, Pål-Tore Selbo; Holst, Martin (Journal article; Peer reviewed, 2018)
      This article outlines a design procedure for variable speed Francis turbines using optimization software. A fully parameterized turbine design procedure is implemented in MATLAB. ANSYS CFX is used to create hill diagrams ...
    • Pump turbines in existing powerplants 

      Dahle, Pål (Master thesis, 2019)
      En brukervennlig metode for å designe kontraroterende aksialpumper har blitt utviklet ved bruk av Matlab. Grafiske brukergrensesnitt har blitt laget for å skrive inn designparametre og å vise designresultater. Designmetoden ...
    • Rotor-Stator Interaction in Low-Specific Speed Francis Turbines 

      Agnalt, Einar (Doctoral theses at NTNU;2019:219, Doctoral thesis, 2019)
      Several breakdowns in hydropower plants with low specific speed Francis runners have been reported. These breakdowns are understood to be related to pressure pulsations, vibration modulus and the combination of these. One ...
    • The Rotor-Stator Interaction Onboard a Low Specific speed Francis Turbine 

      Agnalt, Einar; Solemslie, Bjørn Winther; Storli, Pål-Tore Selbo; Dahlhaug, Ole Gunnar (Journal article; Peer reviewed, 2020)
      Over the last years, several breakdowns in hydropower plants with low specific speed Francis runners have been reported. One of the main excitation forces in such runners is the pressure fluctuations originating from the ...
    • Simulation and Discussion of Models for Hydraulic Francis Turbine Simulations 

      Storli, Pål-Tore Selbo; Nielsen, Torbjørn Kristian (Journal article; Peer reviewed, 2018)
      The paper presents simulations using three different models for a hydraulic turbine. The models are too simple and unrealistic to be used for actual simulations, but the intention is to discuss behaviour intrinsic to the ...
    • Simulations and Measurements of Friction in Oscillating Flow 

      Hamran, Kathrine Albjerk (Master thesis, 2019)
      Friksjonen i massesvingninger i vannkraftverk er ikke tilfredsstillende beskrevet, til tross for at friksjonstapet er viktig for virkningsgraden og stabiliteten til systemet, og optimalisering av kjøreplanen for kraftverket. ...
    • Simulations of the dynamic load in a francis runner based on measurements of grid frequency variations 

      Ellingsen, Rakel; Storli, Pål-Tore Selbo (Journal article; Peer reviewed, 2015)
      In the Nordic grid, a trend observed the recent years is the increase in grid frequency variations, which means the frequency is outside the normal range (49.9-50.1 Hz) more often. Variations in the grid frequency leads ...
    • Two-way coupled simulation of the Francis-99 hydrofoil using model order reduction 

      Tengs, Erik Os; Einzinger, Johannes; Storli, Pål-Tore Selbo (Journal article; Peer reviewed, 2019)
      The Francis-99 hydrofoil is simulated using a quasi two-way Fluid-Structure Interaction procedure. The structural domain is reduced by the use of modal decomposition, and solved for inside the commercial fluid solver ANSYS ...