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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.
Citation preview
Computational Fluid Dynamics
-Key Features & Best Practices
This webinar will be available afterwards at
www.designworldonline.com
Q&A at the end of the presentation
Hashtag for this webinar: #CFDweb
Before We Start
Moderator
Laura Carrabine Design World
David Kan COMSOL
Presenters
Derrek Cooper Autodesk
Wim Slagter ANSYS
Ivo Weinhold Mentor Graphics
Computation Fluid Dynamics –
ANSYS Software Key Features
and Best Practices
Wim Slagter
Lead Product Manager, ANSYS, Inc.
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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
Emag
Acoustics
Structural
CAD Import
Parametric Simulation
Design Exploration
Meshing
Post-processing
Fluid
ANSYS – addressing your current & future CFD challenges
Transient or steady-state Laminar and turbulent flows
Heat transfer
Buoyant flows
Incompressible / compressible
Multi-component flows, multi-phase
Real gas modeling
Filters/porous regions Reactions and combustion
Moving geometry and mesh
Rotating machinery
Solution-based adaptive remeshing
1-way and 2-way Fluid-Structure Interaction Courtesy of GE Energy
Courtesy of BMW AG
Key Enablers:
• Links to almost any CAD system
• Parametric, persistent process
• Simulation focused: allows
engineers to do simulation driven
product development
• Direct modeling allows for re-
animating dumb CAD (geometry
without parameters) models
• Extensive modeling solutions
Engineering Productivity: Geometry Modeling
Bi-directional CAD connections
Feature-Based Modeling
Direct Modeling
CAD Neutral: Direct and
Feature-Based Modeling!
Setup Wizards
Engineering Productivity: Workflow
Geometry
Meshing
Problem Setup
Post Processing
Customized Menus
Increased Productivity through
Automation and Customization!
• Advanced physical models
• High-performance solvers
Engineering Productivity: Accuracy & Speed
User-defined LES for highest accuracy;
RANS for all other areas
RANS
LES Re=395
New steady-state scheme as accurate as transient Wigley hull simulation
Free surface profiles
• Steady-state scheme
• Transient scheme
• Experiment
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Cavitation number
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Hofmann et al [20]
CFD
Recondisation simulation Cavitating flow in a centrifugal pump can also be modeled in steady state
Get reliable answers faster,
without compromise on flow physics!
Integrated Design Exploration & Optimization
Tradeoff Chart
Parametric CAD model
Response Surface and Sensitivity Chart
Section
Length
Guide
Curve
Angle
Guide
Curve
Radius
Eff
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ve
Flo
w A
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Section Length
DOE generated with Design Points
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
Baseline Design Optimized Design
Gain deep insights necessary to
optimize product performance, and
produce better products faster!
Drag sensitivity
Downforce sensitivity
Total pressure drop sensitivity
Total pressure drop sensitivity
Estimated downforce improvement = 41.6N
Actual downforce improvement = 39.1N
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 means of
quickly exploring a design space with
thousands degrees of design freedom!
Shape Sensitivities wrt Design Variables
Fluid Flow
Thermal Stress
Fluid-Structure Interaction
Rigid Body FSI 1-way FSI 2-way FSI
Deformation
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Comprehensive suite of FSI
capabilities for accurate prediction of
a broad range of design scenarios
• 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
Customer Example: Dyson Air Multiplier™ Fan
Courtesy of Dyson
• 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!
Customer Example: Exhaust Manifold
Fluid Flow
Deformation
Von Mises Stress
Temperature
All samples report maximum deformation
below 1.5 mm
Effect of engine speed and thickness at outlet on
maximum deformation
Enabling engineers to get more done
in 24 hours than any other method-
digital or physical!
Derrek Cooper
Product Manager
Autodesk
Background
• Blue Ridge Numerics, Inc.
• Founded in 1992
• Flagship Product = CFdesign
• Leader in upfront CFD
Enabling Technologies
upfront CFD: Fastest way to solving flow & thermal design challenges!
MCAD Connections
Rules
Materials
CAD Groups
Associativity
Configurations iAssys
Instances Templates
Enabling Technologies
upfront CFD: Fastest way to solving flow & thermal design challenges!
Intelligent Automatic Meshing
Enabling Technologies
upfront CFD: Fastest way to solving flow & thermal design challenges!
Intelligent Automatic Meshing
Automatic Mesh Sizing
Geometry Mesh
Diagnostics
Automatic Boundary
Layer Meshing
Mesh Refinement
Regions
Automatic Gap
Refinement
Extrusion Meshing
Powerful Advanced
Tools
Solver Technology
AccelerantTM Finite Element
Solver
Accurate FAST
Intelligent Solution Control
Krylov sparse matrix
solver
Auto Convergence Assesment
Enabling Technologies
Unified Design Study Environment
What If! Cloning
Design Review Center
Critical Values
Pass/Fail Summary
Data
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
Case Study
CFdesign = upfront CFD
upfront CFD: Fastest way to solving flow & thermal design challenges!
Intelligent Automatic Meshing
MCAD Connections
AccelerantTM Finite Element
Solver
Unified Design Study Environment
Thank you…
David Kan
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
Tp uuInf
CFD in COMSOL—Technology
• Finite Element Method
• Accuracy
• Stability
• Meshing
• Compatibility
CFD in COMSOL—Applications
Reactor with free and porous flow
regions
Journal bearing
Inkjet
CFD in COMSOL—Results
Gianluca Argentini of Riello Burners in Legnago, Italy
Thank you!
Dr. Ivo Weinhold
Mentor Graphics Corporation
Mechanical Analysis Division
FloEFD Concurrent CFD Embedded in the Design Process
© Mentor Graphics Corp. 2011 – v2.0
Physical Modeling: 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
Advanced Radiation Model
Physical Modeling: Advanced Radiation Model
Advanced Radiation Model
• Radiation absorption in solids
• Wavelength dependency
• Spectrum definition
• Specularity of surfaces
• Refractive index
Physical Modeling: 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.
Cavitation Model
Source: Wikipedia
Physical Modeling: 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.
Cavitation Model
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
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
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)
AEG Electric Tools - Angle Grinder
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.
Customer Example: AEG Electric Tools – Angle Grinder
www.mentor.com
Questions? Design World Laura Carrabine [email protected] @wtwh_laurac
ANSYS Wim Slagter
COMSOL David Kan [email protected] Phone: 310.441.4800
Autodesk Derrek Cooper [email protected] Phone: 215.717.7265 Twitter: @derrekcooper LinkedIn: .../in/derrekcooper
Mentor Graphics Ivo Weinhold [email protected]
Thank You
This webinar will be available at www.designworldonline.com & email
Tweet with hashtag #CFDweb
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LinkedIn: Design World Group
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