Process Integration and Comprehensive Solution Paradigms: Engine Combustion, Conjugate Heat
Transfer, Durability and Fatigue
Laz Foley, ANSYS Inc.
Outline
• Simulation Trends • CAE in Powertrain Development • Solution Paradigm Challenges and Requirements • A Comprehensive Solution Practice Example
– Turbocharger Design • Conjugate Heat Transfer Work Flows
– Cylinder Head Design • Co-Simulation
– 1D-3D Coupling • Non-Linear FEA
– Gasket Optimization • CAE Toolkit Integration, Automation and Customization
– Solution Scenario: Comprehensive Combustion/CHT Vision Friday, October 03, 2014 2014 Automotive Simulation World Congress 2
Simulation Trends
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Old Paradigms • Single Component
Simulation
• Single Physics
• Few Design Points
New Paradigms • Multi-Domain Simulation
(Component and System)
• Multi-Physics Simulation (flow, thermal, structural, electronic, systems)
• Extensive Design Exploration
CAE in Powertrain Development
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Concept Modeling to Detailed Analysis
Courtesy: BMW AG
Solution Paradigm Challenges and Requirements • Interoperability across physics, scales and
user personas • Workgroup productivity via HPC usage • Design exploration with embedded
capabilities • Integrated multi-physics and co-simulation
with variety of tools in simulation toolkit • Multi-Disciplinary Optimization (MDO) and
Topology Optimization (TO) for all physics disciplines: Structural, Fluids, FSI
• Integrating FMEA work groups with CAE and driving CAT-CAE analyses including simulation as a calibration tool (MiL, SiL, HiL etc.)
• Cloud computing infrastructure, knowledge management, simulation data management/re-use
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Conceptual Design Via Parameterization and Optimization • Parametric CAD Model
– Bi-directional connectivity with Workbench to enable CAD to PPT “push-button” process
– Automated and persistent work flows
– Easily extended to design exploration/optimization
• Non-Parametric CAD Model – Topology Optimization via
mesh morphing (Fluent, RBF-Morph) and/or adjoint methods
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Mesh Morphing Control Volume
Adjoint Shape Sensitivity Contours
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Preliminary Design
Impeller Aerodynamics
Strength and Durability
Full Stage Design & Simulation
Single Physics Verification
Enterprise HPC + Additional Physics
Systems Engineering Robust Design
Key Simulation Applications Within A Turbocharger Design System (Compressor)
Comprehensive and Integrated Design Process
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1D Preliminary Design (VISTA CCD & CCM)
Optimization Loop (Solve with VISTA TF)
Full impeller geometry (BladeModeler)
Stress & Modal Analysis (Mechanical)
Volute Design (DesignModeler)
Volute meshing (ANSYS Meshing)
Post process results (CFD-Post)
Impeller Mesh (TurboGrid)
CFD (one or more points) (HPC execution in CFX)
Blade 3D geometry (BladeModeler)
Pre-Stress Modal (Mechanical)
Impeller CFD (CFX)
Design Life (nCode)
Attach impeller to volute (CFX-Pre)
Turbocharger Durability and Fatigue
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• Fluid-Structure Interaction (FSI) including Conjugate Heat Transfer (CHT)
• Blade Flutter Analysis – Specify blade oscillation via FEM
modal analysis – Calculate aero-damping via CFD
• Forced Response Analysis – Blade excitation forces via CFD – Calculate deformation and stress
via FEM or ROM
• Life Predictions
Conjugate Heat Transfer (CHT) For Combustion System Design
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• Variety of cross-physics and data exchange approaches used – Use of empirical heat data in a
zonal combustion face map – Measured or predicted heat
release profile imposed as energy source in gas exchange CFD model
– Iterative combustion to non-combustion approach
• Challenges include – Different user-personas (Designer,
CFD/FEM analyst), multiple simulation tools (1D/2D/3D), multiple functional groups (CFD, FEA, System)
Courtesy: Mercury Marine
Cylinder Head Temperature Predictions Courtesy: Cummins
CAD to Fatigue for Cylinder Head Design: Process Overview
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CAD to Fatigue for Cylinder Head Design: Key Requirements/Deliverables • Parametric CAD for Design Points and
Optimization • Predictive Combustion (CFD) • Conjugate Heat Transfer Simulation
(CFD) – Head, Liners, Valves, Seats, Guides
etc. – Thermal Resistance/Contact – Boiling
• Thermal/Stress/Fatigue Simulation (FEA) – Non-Linear Materials/Contact,
Gaskets, Bolt Pre-Tension, Threading, Life
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Water Jacket Boiling
Co-Simulation: 1D/3D Coupling
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Diesel Intake Manifold (EGR) Courtesy: Cummins
• Typical Coupling Applications – Intake/Exhaust Manifolds, AIS, Filters,
Mufflers, EGR/PCV, Catalysts, Cylinders • Dynamic Coupling with 1D
Simulation Tools – GT-Suite, WAVE, Virtual Engines for
engine simulation • Solution Benefits
– Capture of complete system level interactions, accurate CFD boundary conditions etc.
– Insights into cylinder-to-cylinder performance, variations etc.
– One coupled engine cycle with ~1M CFD cells < 3h on 64 CPU’s (large model)
Gasoline Intake Manifold
Motorsports: Intake Manifold & Exhaust Cross-Pipe
Non-Linear FEA: Gasket Optimization
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Cylinder Head Gasket Model Courtesy: Cummins
• Durability and Fatigue prediction challenges include – Highly non-linear material – Contact status modeling
• Solution Benefits – Rich suite of hyper-elastic models – Special gasket elements – Curve fitting module to determine
material input from test data
Gasket Components
Soft Gasket Stiff Gasket Compressive Stress Contours
Steady State vs. Transient Loading and Fatigue
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• Steady state loads do not always produce the highest stresses • Cyclic stresses can cause failure at loads lower than material tensile/yield
strength • Transient loading behavior critical for fatigue/life predictions
ANSYS Customization Suite
• Two-Tier Customization Suite – SDK: Workflow and data integration of 3rd
party software – ACT: Custom interfaces for WB/Mechanical
and Beyond
• SDK already used by partners such as nCode, fe-safe and many others
• ACT has been used to customize interfaces and build vertical applications
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CAE Toolkit Integration, Automation and Customization
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Controls, signal processing, embedded software
1D modeling of components (hydraulic, cooling etc.)
1D modeling of components (engine and vehicle)
3D modeling of components and sub-systems, ANSYS as a Server
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Comprehensive Combustion/CHT Solution Vision
Summary
• Some key take ways from this comprehensive solution paradigm – Engine design is much more than developing a combustion
system – Depth and diversity within all physics and at all stages of a design
process is necessary (combustion, fluid, thermal, stress, durability, fatigue)
– Tools and processes that cater to different user personas and disciplines within a design process is important (Designer, Analyst, Systems)
– A collaborative and common platform for integrated CAE is a requirement given product design demands (engine calibration, packaging, controls development, system optimization etc.)
• ANSYS is committed to the continuous advancement of its integrated solution work flows and processes
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