Heat and fluid flow simulations for tomorrow’s energies JP Chabard Sept 2009

2 - THMT 6, H&FF Simulations for energies Information technologies Services to customers and demand-side management Networks Electricity generation Energy management EDF R&D : providing support and preparing the future for all EDF Group business lines Renewables and environmental issues

3 - THMT 6, H&FF Simulations for energies Energy : a worldwide challenge … NPP a very long term investment … World consumption trends in energy medium scenario NPP Gen life : Planning + Construction + Life-span + Dismantling => A century ! Gtep To be found! Renewables Nuclear Coal Gas Oil ? 4,6% 1,9% 1,4% - 0,5% Plant life = years

4 - THMT 6, H&FF Simulations for energies OUR WORLD Water : anticipating climate constraints on shared resources Continuous improv’t in characterization of environmental impacts of our facilities R&D challenges for EDF Group GENERATION Enabling 60 year lifespan for nuclear power plants Integrating new technologies for more efficiency Innovating in renewable energies and storage CUSTOMERS Built Envir’t. : technologies & services for energy efficiency Industry : developing energy efficiency & new electric usage GRIDS Preparing the 2015 distribution network OPTIMIZATION Anticipating the new energy landscape Generation optimization into the market : re-establishing methods and tools Finding flexibility between consumption, generation and storage MODELLING and SIMULATIONS to support DECISIONS !

5 - THMT 6, H&FF Simulations for energies Verification and Validation (V&V) in CFD Simulations for Decisions: Nice, but where are the error bars? X 50 reactors => 100 Billion Euros.. Industrial CFD with RANS Many Indust OK with “approximate” predictions Aerospace: reduce Drag by 1 % important Power Gen. Nusselt number +/- 10 % is OK But need some sort of error bars ! No best overall RANS model Heat Transfer more difficult RANS CFD is Mature ? Academic research => DNS, LES, Fundamental Turbulence mechanics Not much progress expected from RANS developments ? CFD progress mainly from bigger computers !

6 - THMT 6, H&FF Simulations for energies Best Practice Guidelines and Database Initiatives … an enduring aspiration EDF R&D involved since 1980 in IAHR - ERCOFTAC V&V activities … Refined Modelling of Turbulent Flows workshops Org. by Viollet, Launder, Hutton, Rodi, Hanjalic, Jakirlic… 14 th workshop here this Friday ! ERCOFTAC Best Practice Guidelines (2000) … IAHR 1980 !

7 - THMT 6, H&FF Simulations for energies Best Practice Guidelines and Database Initiatives “Classic collection” administered by Dr. Craft at Manchester over 80 test-cases for V&V of CFD on turbulent flow Many of its test cases used for Validation of Code_Saturne. But only expt. data, no model testing “QNET-CFD Trust and Quality in CFD” Was major EU project, contribs. from 40 part. HTML format + adds QA to classic collection But hard to extend when funding stopped Currently turned into a “wiki” by Ercoftac OECD Nuclear Energy Agency's “BPG for use of CFD in reactor safety applications” (2007) Classic “paper report” format, or compilation of (old) reports; sections of variable quality Ignores previous V&V activity. Not aware of EDF CFD software ! No serious RANS test case, Poor understanding of RANS, Advertises fashionable but scarcely validated (besides aerodynamics) RANS-LES models Was this independent initiative necessary?

8 - THMT 6, H&FF Simulations for energies Fashionable RANS-LES Blending: Too recent, not enough validation Detached Eddy Simulation Scale Adaptive Simulation Unsteady RANS RANS

9 - THMT 6, H&FF Simulations for energies “Wikipedia” type website for V&V Academic publications report success rather than failures: much overselling of “turbulence model improvements” One-time funded EU/Gov projects => valuable, but rapidly obsolescent websites Further funding in CFD and Turb. Mod. harder to secure “Wikinomics” and the Wikipedia model could be the answer. Definition “Mass collaboration, relying on individuals cooperating freely to solve a problem or improve know-how” seems particularly suited to deal with V&V of software” A sample of “Wikipedia” type of web-database initially for U. Manchester – EDF collaboration around Code-Saturne PhD students uploaded their test cases AND results Used by growing community of CFD users, Now contains not only ref data, but also meshes, parameter files, result files, model comparisons, for several codes Several codes, same model => reference solution Will be used for validation of next code_saturne releases, instead of internal reports Self-sustainable if/when critical mass reached: Even if only 10% of wiki users contribute, 10% x 2000 = lot of contributors !

10 - UoM-EDF Wiki Collaborative Website : sample test cases