Update Seminar. CAE Associates Inc. and ANSYS Inc. Proprietary 2013 CAE Associates Inc. and ANSYS Inc. All rights reserved.

Transcription

1 ANSYS CFD v14.5 Update Seminar CAE Associates Inc. and ANSYS Inc. Proprietary 2013 CAE Associates Inc. and ANSYS Inc. All rights reserved.

2 Outline Design Iteration/Optimization using CFX and DX Demo One-way FSI ANSYS Meshing v14.5 ANSYS CFX v14.5 ANSYS Fluent v14.5 Shape Optimization using Fluent Adjoint Method Demo 2

3 Design iteration/optimization in DX 3

4 Outline Design Iteration/Optimization using CFX and DX Demo One-way FSI ANSYS Meshing v14.5 ANSYS CFX v14.5 ANSYS Fluent v14.5 Shape Optimization using Fluent Adjoint Method Demo 4

5 Fluent Meshing - TGrid Fluent Meshing Mode (integrated Tgrid) )for advanced CFD meshing Faceted-CAD based meshing: Import from CAD, Mesh and STL Foundation for future parallel l meshing Faster turnaround for cases with large, complex meshes No file I/O between meshing and solving Mesh in serial then solve in parallel via dynamic process spawning Automate and customize via Scripting Fluent (with TGrid meshing) in Workbench CAD import Solver parameters User interface of the Fluent Meshing Mode. (Displayed model depicts human stomach imported directly into Fluent in STL format). New Fluent (with TGrid meshing) component available in Component Systems and added in Project Schematic 5

6 Fluent meshing CutCell 6

7 Fluent Meshing -- TGrid Advanced CFD meshing for large-scale, complex meshes Wrapper technology for massive geometry simplification and surface (re)meshing Advanced prism/tet/hexcore meshing for large meshes > 100 million cells Size functions, inflation, and assembly meshing Extended meshing and mesh editing controls and tools Scripting ANSYS Meshing backup tool CAD import, size functions, surface meshing, inflation, assembly meshing Wrapper Tet HexCore with Inflation Cavity Re-meshing CutCell 7

8 How can Fluent Meshing extend WB Meshing? Workbench Meshing is the proposed meshing solution, Fluent Meshing is a complement. With Workbench Meshing, you have ease-of-use,,parametric and persistence throughout the meshing process. But if the time/quality does not meet client needs for a specific model, Fluent Meshing could be your back-up solution. Note that geometry/mesh changes are not parametric with Fluent Meshing, except using advanced scripting Fluent Meshing has extended capabilities to produce high quality meshes Fluent Meshing is directly available to all Fluent users without any additional cost or licenses 8

9 ICEM CFD Patch Independent technology Dirty CAD, third party geometry, etc Faceted data, scan data, STL Combinations of CAD, facets, mesh Efficiently mesh large/complex models with extended mesh controls Integrated geometry and meshing solution Hexa mesh, structured or unstructured, with automatic (MultiZone) or advanced interactive blocking control Extended mesh diagnostics and advanced, interactive mesh editing Flexible output for many solvers CFD, FEA, neutral formats Available from Workbench Interacti ve Mesh Editing >250 million cell assemblies Structurt ed Hexa mesh 9

10 ICEM CFD 14.5 in Workbench Similar to other Workbench systems Can drop on to a Design Modeler system or a Workbench Meshing system Transfers geometry and/or mesh 10

11 Outline Design Iteration/Optimization using CFX and DX Demo One-way FSI ANSYS Meshing v14.5 ANSYS CFX v14.5 ANSYS Fluent v14.5 Shape Optimization using Fluent Adjoint Method Demo 11

12 Mesh Motion Constrained Parallel to Boundary Surface mesh is allowed to slide over original boundary mesh No underlying geometry representation ti nor parameterization is required More complex geometry motion is possible with a single mesh topology Further minimize the need for interpolation between meshes Mesh quality (e.g. orthogonality) is maintained over larger range of motion Less user-specified mesh motion controls are required Check valve with solution dependent geometry motion, showing improved the mesh quality as the ball oscillates to a steady position 12

13 Mesh Motion Constrained to Surface of Revolution The user defines the axis of rotation The surface mesh is allowed to slide on the surface defined by axis and radial profile from initial boundary mesh Assumes constant radius at each axial position Allows mesh motion beyond initial boundary mesh Key application is blade flutter (turbomachinery) Oscillating blade tip motion slides on shroud surface Improved robustness to greater amplitudes Maintains the mesh quality Surface of Revolution boundary condition for mesh motion constraint on moving valve and fluttering blade 13

14 Mesh Displacement Relative to Initial Mesh Important feature for periodic motion Avoids accumulation of error over time Ensures consistent mesh from cycle to cycle Typical applications Piston motion Blade oscillations Simulation of a vibrating turbine with prescribed oscillatory blade motion normal to the blade chord, where consistent mesh is essential 14

15 Transient Blade Row Methods Continuous focus of turbomachinery development in recent releases and going forward in future releases Aim to minimize computational effort (CPU and Memory) for accurate simulation of transient t interaction ti between blade rows Introduced in R14.0, enhanced and extended with R14.5 TBR methods require only 1-2 blade passages per blade row while still capturing transient interaction ti accurately TBR methods are designed for efficient simulation of transient interaction ti where the pitch between blade rows is unequal (i.e. a b) 15

16 Transient Blade Row Applications Multistage Gust Analysis Gust Analysis Blade Flutter Blade Flutter IBPA Damping Coef. Blade Row displacement Single Stage Period 2 j Nb j 0 Nb 1 IBPA 16

17 Blade Flutter Analysis Pragmatic approach to assess propensity to flutter Determine natural frequency of blade and its mode shapes, in a modal analysis Apply specified blade motion, based on modal analysis, in fluids simulation Assess system stability, looking at aerodynamic damping of prescribed blade vibration Result: prediction of whether or not blade will flutter Can be applied to full wheel or use Fourier Transformation (FT) TBR method Numerous related enhancements in support of this type of blade flutter analysis support of this type of blade flutter l h b d ( ) d Axial compressor with prescribed motion (top) and resultant pressure fluctuations at 90% span (bottom) 17

18 Blade Flutter Analysis Export p of mode shapes p from a modal analysis in ANSYS Mechanical with new functionality to create CFX profile file Profile visualization and rendering g to verify profile alignment/scaling, check geometry y condition New mesh motion boundary option for periodic displacement User need only specify mode shape (profile), frequency, scale factor and phase angle Solver assessment of work/power (per unit area) on the blade to assess aeroelastic damping of the applied motion Related general enhancements Mesh motion, solution monitoring, Details on other slides The ability to visualize imported profiles allows a priori confirmation of proper alignment of mesh and profile 18

19 Workbench Integration of Vista CPD Vista CPD (Centrifugal Pump Design) Native Workbench application Ability to use Vista CPD directly create Blade geometry model Throughflow analysis Volute geometry and mesh 19

20 RPI Wall Boiling Model Enhancements Model robustness improvements Additional control and flexibility Under-relaxation specification of wall superheat Consistent under- relaxation of individual wall heat partition components User-specified area factors β User-specified additional components of wall heat partition β Key target application is fuel bundle cooling simulations R14.5 R14.0 Much improved convergence in a simulation of DEBORA test facility, thanks to new underrelaxation improvements (Courtesy HZDR) 20

21 MAPDL Outputs Component for CFD-Post MAPDL outputs component file (*.cm file) for CFD-Post Allows CFD-Post to read Named Selections and boundary condition regions set in Mechanical. Easier to post-process Mechanical results in CFD- Post for FSI simulations. 21

22 Outline Design Iteration/Optimization using CFX and DX Demo One-way FSI ANSYS Meshing v14.5 ANSYS CFX v14.5 ANSYS Fluent v14.5 Shape Optimization using Fluent Adjoint Method Demo 22

23 Monitor Fluent Solutions in Workbench Monitor the convergence when Fluent is running in the background Track simulation convergence while updating design points Track simulation convergence when using RSM Example of a FLUENT Residual Chart View Within Workbench 23

24 Design Explorer with Mesh Morpher Use Fluent Mesh Morpher and Optimizer (MMO) parameters with Design Explorer (DX) Leverage the extensive optimization capabilities of DX with Fluent MMO More sophisticated optimization Parameter constraints Multiple objectiveses 24

25 System Coupling in Workbench Native Workbench application for multiphysics coupling Currently supports Fluent and Mechanical solvers User interface fully integrated in Workbench environment Extensible architecture for range of coupling scenarios One-, two- & n-way, static data, co-simulation 25

26 One-way Thermal Data Transfers In Fluent thermal boundary conditions set via System Coupling allow the specification of temperature or heat flow on surfaces via System Coupling. 26

27 One-way Thermal Data Transfers In Mechanical a Fluid-Solid Interface can be specified in a Steady-State Thermal System on surfaces. The Fluid-Solid Interface automatically writes the temperature and heat flow results to an AXDT file format to the solver directory. The Fluid-Solid Interface also accepts thermal data as a boundary condition from System Coupling. 27

28 Contact Detection for Moving Meshes Contact detection for valves, FSI, and other applications Detects when surfaces come within a specified tolerance and prevents collision of moving zones User defines how to treat contact region and whether to restrict flow Default porous media zone treatment UDF hooks to define contact behavior Not currently compatible with Systems Coupling Contact detection in a case where the opposite sides of a box deform in a sinusoidal wave pattern Contact detection used in a bouncing ball case 28

29 New Non-Reflecting Boundary Conditions Non-Reflecting Boundary Conditions with the Pressure- Based Solver eliminate unphysical reflections from flow boundaries during unsteady simulations Compatible with species transport and combustion Compatible boundary types: Pressure outlets Pressure inlets Mass flow Inlets Velocity inlets/outlets Pressure pulse Reflecting Non reflecting 29

30 Improved Prediction of CO Faster and more accurate premixed flamelet model for Carbon Monoxide (CO) emissions Based on the Flamelet Generated Manifolds (FGM) approach Solves transport equations for mixture fraction (mean and variance) and reaction progress (mean and variance) Contours of CO mole fraction Best suited for perfectly premixed combustion 30

31 Versatile DPM Injections Transient spray angle profile for cone injections Spray angle as function of time or crank angle via profiles Cone injections for sector meshes Simulate a pizza slice of axisymmetric geometry New parcel release methods for DEM and sprays By default, a single parcel is injected per injection stream per time step New parcel release methods: Constant parcel diameter or constant mass for DEM Constant number of particles per parcel for spray simulations 31

32 Improvements for Eulerian Wall Film Modeling Adaptive time stepping speeds up transient t calculations l Improved accuracy: Account for surface tension effects in film momentum equations Random locations of DPM 3D Wing with Slats & Flap injections capture film separation physics more accurately New modeling capabilities: Coupling of EWFM with mixture and Eulerian multiphase models, including thermal coupling Condensation-vaporization Design of anti-icing icing system of Eulerian wall films Prediction of the trajectory 32

33 Accurate modeling of Marangoni Convection Surface tension as a function of space variable (e.g. species concentration) for more accurate modeling of Marangoni convection Important applications include: Coating Welding Microfluidics Film drainage in emulsions and foams Drying of semiconductor wafers Co onstant surfa ace ten nsion rface tion of tration) Variable sur nsion (funct anol concent V ten etha water Alcohol drop falling in water Liquid volume fraction Liquid ethanol Ethanol concentration 33

34 Compressible VOF Liquid Modeling Liquid id compressibility improves pressure prediction at start-up and provides better solution stability/convergence with moving deforming meshes Available for both single phase and multiphase models Appropriate for high pressure applications Sound speed post- processing is available for compressible liquid Box initially half submerged in water Contours of pressure after the 10 th time step Compressible Liquid (Good results) Incompressible Liquid (Unphysical results) 34

35 Better Parallel Scalability with Particles Improved DPM parallel scalability via Improved memory management 2 examples: 10 million cell combustor case scales well overall to 1024 cores (example to right) 10 illi ll For another typical customer 250 DPM case: time on 24-way 200 parallel reduced from 20.4s to s 100 Ra ating Overall Scalability for a 10 million cell Combustor Simulation CRAY XE AMD 2.1GHz IL NumCores 35

36 Faster Linear Solver Thanks to GPUs β Algebraic Multi-Grid (AMG) Solver on GPUs β Accelerates AMG solver for 3D coupled pressure- based solver cases Available in serial and shared memory parallel Fluent Supported on NVIDIA Fermi based GPUs with CUDA 4.1 and above 36

37 Outline Design Iteration/Optimization using CFX and DX Demo One-way FSI ANSYS Meshing v14.5 ANSYS CFX v14.5 ANSYS Fluent v14.5 Shape Optimization using Fluent Adjoint Method Demo 37

38 Adjoint Method Adjoint Solver for Fluent Fully supported in v14 Provides information about a fluid system that is very difficult and expensive to gather otherwise Computes the derivative of an engineering quantity with respect to inputs for the system Engineering quantities available Down-force, drag, pressure drop Robust for large meshes Tested up to ~15M cell Shape sensitivity to down-force on a F1 car Lift Force (N) Geometry Predicted Result Original Mod Mod Mod Shape sensitivity to lift on NACA

39 More Capabilities for the Adjoint Solver New compound observables for the Adjoint Solver Specify observables specifically for the engineering purpose (e.g. lift/drag ratio, mass flow rate variance) Easily define global improvement direction (minimize or maximize) Use the Adjoint solver in cases with periodic boundary conditions Translational and rotational periodics SRF, MRF, and sliding mesh are not supported R14: Minimize drag OR maximize i lift 2D translation periodic example, showing optimal displacement vector field to improve lift/drag for the blade R14.5 Maximize (Lift/Drag) ratio 39