for hydropower using OpenFOAM Bercelay Niebles Atencio Department - PowerPoint PPT Presentation

Heat transfer studies in electric generators for hydropower using OpenFOAM Bercelay Niebles Atencio Department of Mechanics and Maritime Sciences CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden, 2017

Electric Generator Design Currently - Design phase of electric generatos relies on empirical correlations (network models). - Large uncertainties (up to 25% error). - Flow of cooling air has been studied in the past. - Many studies focused on flow, thermal models, few experiments. - Nothing done in openFOAM regarding heat transfer in hydrogenerators .

Electric Generators for Hydropower Sketch of an electric generator for hydropower. Source: http://www.eternoohydro.com/hydro-generator/

Solvers in openFOAM - Conjugate heat transfer processes: chtMultiRegionSimpleFoam - Rotation of fluid: MRFSimpleFoam

Code Modification • Use chtMultiRegionSimpleFoam as base sover • Addition of rotation • Addition of heat source terms in heat equation for solids • Test

Testing the code modification

Temperature Boundary Conditions T

With Heat Source term Heat

Network Models Stator Core Rotor Outer Inner - One slot -Heat generation (coil, core) -No rotation -Periodicity and symmetry

CFD for Network Model Case Nusselt Number Re CFD Gnielinksi Dittus-Boelter 3152 15.7 7.9 12 3520 16.8 9.1 13 3960 17.5 10.4 14.3

CFD for SVANTE • Run for different Re • Run for different heat sources • Post-processing • Find correlation Nu, Re and Pr? • Compare with correlations in Network Models

Hydro-generator model experimental rig

Experiments Naphthalene Sublimation Technique Air passage Top Bottom

Naphthalene Sublimation Naphthalene

Simulations for the hydro-generator model Inlet -Inlet, rotor, stator cellZones -kOmegaSST – low Re Rotor -MRFSimpleFoam + heat Stator -Periodic -Mixing Plane -Flow field -Heat transfer in stator channels

Simulations

Thank you!