CFD Best Practices & Key Features
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Computational fluid dynamics (CFD) is a powerful tool to simulate, analyze, and optimize designs. The leading CFD providers will discuss software features and functionality such as flow features and benefits, solver technology, as well as describe an example of CFD use in the real world.
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CFD Best Practices & Key Features
- 1. Computational Fluid Dynamics -Key Features & Best Practices
- 2. Before We Start This webinar will be available afterwards at www.designworldonline.com Q&A at the end of the presentation Hashtag for this webinar: #CFDweb
- 3. Moderator Laura Carrabine Design World Presenters David Kan Wim Slagter Ivo Weinhold COMSOL ANSYS Mentor Graphics Derrek Cooper Autodesk
- 4. Courtesy of Borg Warner Turbo & Emissions Systems Wim Slagter Lead Product Manager, ANSYS, Inc. Courtesy of CADFEM Russia Computation Fluid Dynamics – ANSYS Software Key Features and Best Practices
- 5. ANSYS, the company • ANSYS design, develops, markets and globally supports a comprehensive range of engineering simulation software • Proven software technologies for o Fluid Dynamics o Structural Mechanics o Acoustics o Electromagnetics o Multiphysics • Specialized tools, incl. o ANSYS Icepak (thermal/flow for electronics) o ANSYS nCode DesignLife (for fatigue) • World’s largest pool of experts providing CFD Best Practices Design Exploration Parametric Simulation Emag Structural Fluid CAD Import Acoustics Postprocessing Meshing
- 6. ANSYS – addressing your current & future CFD challenges Transient or steady-state Heat transfer Laminar and turbulent flows Moving geometry and mesh Buoyant flows Rotating machinery Solution-based adaptive remeshing Incompressible / compressible Real gas modeling Multi-component flows, multi-phase Courtesy of BMW AG Reactions and combustion Filters/porous regions 1-way and 2-way Fluid-Structure Interaction Courtesy of GE Energy
- 7. Engineering Productivity: Geometry Modeling Key Enablers: • Links to almost any CAD system • Parametric, persistent process • Simulation focused: allows engineers to do simulation driven product development CAD Neutral: Direct and • Direct modeling allows for reFeature-Based Modeling! animating dumb CAD (geometry without parameters) models • Extensive modeling solutions Bi-directional CAD connections Feature-Based Modeling Direct Modeling
- 8. Engineering Productivity: Workflow Geometry Meshing Problem Setup Setup Wizards Customized Menus Post Processing Increased Productivity through Automation and Customization!
- 9. Engineering Productivity: Accuracy & Speed • Advanced physical models • High-performance solvers Free surface profiles • Steady-state scheme • Transient scheme • Experiment RANS New Get reliable steady-state scheme as accurate as transient Wigley hull simulation answers faster, Re=395 User-defined LES for highest accuracy; without compromise on flow physics! LES RANS for all other areas Head rise coefficient 1.0 Hofmann et al [20] CFD 0.9 0.8 0.7 0.6 0.5 0.4 0.0 0.5 1.0 1.5 Cavitation number Cavitating flow in a centrifugal pump can also be modeled in steady state Recondisation simulation
- 10. Integrated Design Exploration & Optimization Parametric CAD model Effective Flow Area Guide Curve Radius Guide Curve Angle Section Length Section Length Response Surface and Sensitivity Chart Gain deep insights necessary to optimize product performance, and produce better products faster! Baseline Design Optimized Design Tradeoff Chart Guide Curve Angle (Deg) Guide Curve Radius (mm) Section Length (mm) EFA (mm2) Baseline 63 41 51 1100.2 Optimized 50 30 60.5 1180.4 DOE generated with Design Points
- 11. Shape Sensitivities wrt Design Variables Adjoint flow solver: • An understanding of the shape sensitivities with respect to design variables in a single computation! • A quantitative performance estimate due to a design change without the need to simulate the actual change! Adjoint is a very efficient Total pressure drop sensitivity means of quickly exploring a design space with thousands degrees of design freedom! Drag sensitivity Estimated downforce improvement = 41.6N Actual downforce improvement = 39.1N Downforce sensitivity Total pressure drop sensitivity
- 12. Fluid-Structure Interaction Rigid Body FSI 1-way FSI 2-way FSI Fluid Flow Comprehensive suite of FSI capabilities for accurate prediction of a broad range of design scenarios Deformation Courtesy of Embraco Thermal Stress
- 13. Customer Example: Dyson Air Multiplier™ Fan • Design objective: o Maximize amplification ratio for a given size and power consumption o 3 main design parameters, i.e. gap in annular ring, internal profile of ring, profile of external ramp • Customer benefits include: o Explored 10-fold of design variations than would otherwise have been possible (each day 10 instead of 1) o Improved performance 250% over original design Courtesy of Dyson
- 14. Customer Example: Exhaust Manifold • Design objective: o To optimize the dual-outlet exhaust manifold for robust performance o 4 main design parameters, i.e. outlet diameter of the manifold, thickness at inlet, external temperature, engine RPM • Design constraint: o Maximum displacement should not exceed 1.5 mm! Temperature Deformation Effect of engine speed and thickness at outlet on maximum deformation Fluid Flow All samples report maximum deformation below 1.5 mm Von Mises Stress
- 16. Enabling engineers to get more done in 24 hours than any other methoddigital or physical! Derrek Cooper Product Manager Autodesk
- 17. Background • Blue Ridge Numerics, Inc. • Founded in 1992 • Flagship Product = CFdesign • Leader in upfront CFD
- 18. upfront CFD: Fastest way to solving flow & thermal design challenges! Enabling Technologies CAD Groups MCAD Connections Templates Materials Rules Configurations iAssys Instances Associativity
- 19. upfront CFD: Fastest way to solving flow & thermal design challenges! Enabling Technologies Intelligent Automatic Meshing
- 20. upfront CFD: Fastest way to solving flow & thermal design challenges! Enabling Technologies Geometry Mesh Diagnostics Intelligent Automatic Meshing Automatic Mesh Sizing Mesh Refinement Regions Automatic Boundary Layer Meshing Extrusion Meshing Automatic Gap Refinement Powerful Advanced Tools
- 21. Solver Technology Accurate FAST AccelerantTM Finite Element Solver Krylov sparse matrix solver Intelligent Solution Control Auto Convergence Assesment
- 22. Enabling Technologies What If! Unified Design Study Environment Cloning Critical Values Design Review Center Pass/Fail Summary Data
- 23. Case Study Lighting manufactures moving to LEDs due to longer life & better performance Challenge- Temperatures must remain lower than traditional lighting The cooler it is, the longer it lasts Rule of thumb – airflow is as important as surface area
- 24. Case Study
- 25. upfront CFD: Fastest way to solving flow & thermal design challenges! CFdesign = upfront CFD Intelligent Automatic Meshing MCAD Connections AccelerantTM Finite Element Solver Unified Design Study Environment
- 26. Thank you…
- 27. David Kan
- 28. CFD in COMSOL—Principles • Ease-of-use o Tailored functionality and interfaces o Robust • Efficiency o State-of-the-art performance o Accurate • Multiphysics o Fluid flow with any physics combination Fluid flow past a solar panel f n pI u u T
- 29. CFD in COMSOL—Technology • Finite Element Method • Accuracy • Stability • Meshing • Compatibility
- 30. CFD in COMSOL—Applications Reactor with free and porous flow regions Inkjet Journal bearing
- 31. CFD in COMSOL—Results Gianluca Argentini of Riello Burners in Legnago, Italy
- 32. Thank you!
- 33. FloEFD Concurrent CFD Embedded in the Design Process Dr. Ivo Weinhold Mentor Graphics Corporation Mechanical Analysis Division © Mentor Graphics Corp. 2011 – v2.0
- 34. Physical Modeling: Advanced Radiation Model Advanced Radiation Model • Radiation is one of the three fundamental methods of heat transfer • A radiation model must consider the complex physics involved in radiative heat transfer • Correct radiation simulation is essential for the correct prediction of the temperature distribution in many designs • Radiation plays an important role for simulations of fluid flow and heat transfer in automotive, building design, electronics cooling, and many more
- 35. Physical Modeling: Advanced Radiation Model Advanced Radiation Model • Radiation absorption in solids • Wavelength dependency • Spectrum definition • Specularity of surfaces • Refractive index
- 36. Physical Modeling: Cavitation Model Cavitation Model • Cavitation describes the process of vaporisation, bubble generation and bubble implosion in a flowing liquid as a result of a decrease and subsequent increase in pressure if the pressure declines to some point below the saturated vapor pressure of the liquid. • It can occur in control valves, pumps, propellers, impellers, etc. • The shock waves formed by cavitation are strong enough to significantly damage moving parts. Therefore cavitation is usually an undesired effect. • Cavitation is a major field in the study of fluid dynamics. Source: Wikipedia
- 37. Physical Modeling: Cavitation Model Cavitation Model FloEFD includes two cavitation modeling approaches: • Engineering cavitation model (for water only): • This model employs a homogeneous equilibrium approach and has the capability to account for thermal effects. • Isothermal cavitation model: • This model is based on the approach considering isothermal two-phase flows for user-defined incompressible liquids. Reference: Wesley, H. B., and Spyros, A. K.: Experimental and computational investigation of sheet cavitation on a hydrofoil. Presented at the 2nd Joint ASME/JSME Fluid Engineering Conference & ASME/EALA 6th International Conference on Laser Anemometry. The Westin Resort, Hilton Head Island, SC, USA August 13 - 18, 1995
- 38. Solver Technology: Numerical Schemes Numerical Schemes • Cell centered finite volume method • Unified implicit method for both incompressible and compressible liquids and slightly compressible gas flows; Explicit method for high Mach number flows • Coupled solver for momentum equations • Conjugate formulation for heat transfer calculation in fluid and solid • Second order scheme for approximation of conservation laws in fluid and solid • Monotonic scheme for incompressible tasks • Multigrid method for linear algebra solver • CPU time per cell and iteration is independent from cell count
- 39. Solver Technology: Mesh Generation Mesh Generation • Automatic meshing of fluid and solid regions • Immersed Boundary Cartesian mesh technology • Automatic mesh refinement/unrefinement due to geometrical and/or physical (solution adaptive) requirements • Special cost-effective treatment of thin solids and thin channels • Automatic immersed boundary treatment (near-wall physics)
- 40. Customer Example: AEG Electric Tools – Angle Grinder AEG Electric Tools - Angle Grinder
- 41. Customer Example: AEG Electric Tools – Angle Grinder Design Challenge: • Optimize housing openings for cooling performance, dust protection and safety requirements Benefits: • The new design protects the motors from abrasive dust while the optimized airflow prevents dust accumulation in sensitive areas such as the switch and electronics. • It guarantees a better cooling effect – all of which lead to an up to 10 times longer tool lifetime than competitive angle grinders with metal dust chambers.
- 42. www.mentor.com
- 43. Questions? Design World Laura Carrabine lcarrabine@wtwhmedia.com @wtwh_laurac ANSYS Wim Slagter wim.slagter@ansys.com Mentor Graphics Ivo Weinhold ivo_weinhold@mentor.com COMSOL David Kan david.kan@comsol.com Phone: 310.441.4800 Autodesk Derrek Cooper derrek.cooper@autodesk.com Phone: 215.717.7265 Twitter: @derrekcooper LinkedIn: .../in/derrekcooper
- 44. Thank You This webinar will be available at www.designworldonline.com & email Tweet with hashtag #CFDweb Connect with Twitter: @Design_World Facebook: /engineeringexchange LinkedIn: Design World Group Discuss this on EngineeringExchange.com