ansys cfx release 17 - enginsoft - software e … blade row methods with pitch-change ansys cfx...
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ANSYS CFXRelease 17.0
Areas of DevelopmentTurbomachinery Blade RowWorkflowGeneral Physics ModelingUser Environment
TURBOMACHINERY BLADE ROW
3
Blade Row: Mixing Plane ImprovementsChanged default downstream velocity constraint to ‘Total Pressure’
Permits downstream velocity profile to naturally adjust to downstream influences
Improved energy closureHigher solution accuracyReduce reflections at interface
R16
R17
Transient Blade Row Methods With Pitch-ChangeANSYS CFX transient pitch-change models
Profile Transformation
(PT)
Time Transformation
(TT)
Fourier Transformation
(FT)Small/Moderate Pitch
• Single Stage • Multistage
• Frozen gust • Single Stage • Multistage
• Frozen gust • Single Stage • Multistage • Blade Flutter
Small/Moderate Pitch Large Pitch
PT TT FT
Transient interaction +
Correct blade passing frequencies
Transient interaction
Full-wheel Model
Reduced Model
Solve on Reduced Geometry
Transient Blade Row MethodsExtended models and improved usability
Time Transformation and Fourier TransformationMulti-stage, Asymmetric flow, Multi-disturbance
Transient Blade Row with CHTMixing plane improvementsConvergence monitoring for cyclically periodic flow ( )Harmonic Analysis: frequency-domain method ( )
Transient Blade Row: TT for MultistageModeling multistage with combination of TT and Single-Sided Time Transformation (STT) interfaces
Flexibility in modeling multi-stage with combination of TT, STT and PT interfaces for wide range of machinesFurther improvement to aerodynamic performance prediction
Transient Blade Row: FT-TRS with AsymmetryCoupling single rotor passage to 360 domain with Fourier Transformation (FT)Handle single and multi-frequential disturbances
Examples of large single disturbance
Example of large multi-frequential disturbances
Compressor operating off-design - Fan in crosswind- Boundary layer ingestion- Ground vortex ingestion
Impeller in a vaneless volute
Impeller in a vaned volute, with two disturbances seen by rotor1) diffuser blade passing2) one-per-rev variation due to volute
Transient Blade Row: FT Multi-disturbanceFourier Transformation (FT) with multiple disturbances
Frozen gust analysis with inlet and outlet disturbances
Transient Blade Row: FT for MultistageFourier Transformation (FT) with
multiple pitch ratiosmultiple frequencies
All the benefits of FT method – now also for multi-stage analysis
Incompressible fluidsLarge pitch ratioetc.
Transient Blade Row: with CHTAltered solid thermal response to combine CHT with TBR
Transient Blade Row: UsabilityCyclic and polar plots in solver monitors ( )
Overlay multiple common blade passing periods Clear visualization of convergence to quasi-steady solutionVisible beta feature
TBR restart with time-step size changeStop FT or TT and then resume with larger time stepReduce the overall simulation time required to reach convergence
Transient Blade Row: Harmonic Analysis ( )Introduction of frequency-domain method
A priori specification of resolved frequencies highest solution efficiencyAdvanced implementation with numerous advantages
Truly non-linear, no shock smearing, …
Can be used with all existing pitch-change methods
Full wheel, PT, TT, and FT
Rotor 67 fan test case: equivalent results to full wheel, but ~10X faster than with FT
and ~50X faster than full wheel
WORKFLOW
14
User Location (Surface) OutputResults output to arbitrary surface locations
Generate significantly less dataLeaner simulation and analysis
Significant impact for large transient cases
Data (disk space) may be reduced by orders of magnitudeLess data sent between CFD-Post engine and GUI during post-processing
Analogous capability for Fluent and CFX
Arbitrary surface output location (independent of solver mesh)
Live CFX Solution Monitoring in CFD-Post ( )Building on “User Surface” output
FSI with CFX and Systems Coupling 2-Way FSI between CFX and Mechanical
Supersede MFX with workflow and technology consistent with Fluent-Mechanical couplingInitial support for steady and transient exchange of forces and resultant displacements
GENERAL PHYSICS MODELING
18
Intermittency Transition ModelOne-Equation Intermittency-based Transition Modelling
Significant advancement of the -Remodel
Reduce number of equationsGalilean invariantSimplified correlationsCrossflow instability
Advances in Scale-Resolving Turbulence ModellingNew Shielded Detached Eddy Simulation (SDES)
Stronger shielding than Delayed DESClear separation of RANS and LES modeNew option for existing DES SST
New Stress-Blended Eddy Simulation (SBES)
Incorporates and builds on SDESFaster switch to LES modesCombine RANS and LES, with blending (f)
Currently using SST and WALE LES Blended eddy viscosity
SBESLEStSBES
RANSt
SBESt ff 1
USER ENVIRONMENT
23
CFD-Post Charts of CFX Monitor DataAccess to CFX monitor data for use in charts in CFD-PostInclude convergence plots in reports generated with CFD-Post
Time AnimationEase-of-use for transient post-processing
‘Music player’-like controlPlay/stopNext/previous time stepFirst/last time step
Options toSpecify desired transient range by time step, time, or crank angleControl which frame to use when between available framesSave time animation to movie file
GUI-Engine Communication EfficiencyAvoid compression/decompression during data transferImprove interactive efficiency/performance
More data transferredBut: no compression/decompression cost
R16 R17
Support for STL SurfacesAbility to import/export *.stlformat geometry definition
Define post-processing locations Import as contextual geometryExport any surface locator for other uses
e.g. surfaces in Fluent
Original CAD geometry surfaces around flow domain brought in as STL to give improved context to simulation results