ANSYS CFX Release 17.0

ANSYS CFX Release 17.0 Areas of Development ƒ ƒ ƒ ƒ Turbomachinery Blade Row Workflow General Physics Modeling User Environment TURBOMACHINERY BL...
Author: Lester Haynes
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ANSYS CFX Release 17.0

Areas of Development ƒ ƒ ƒ ƒ

Turbomachinery Blade Row Workflow General Physics Modeling User Environment

TURBOMACHINERY BLADE ROW

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Blade Row: Mixing Plane Improvements ƒ Changed default downstream velocity constraint to ‘Total Pressure’ ƒ Permits downstream velocity profile to naturally adjust to downstream influences

R16

ƒ Improved energy closure ƒ Higher solution accuracy ƒ Reduce reflections at interface

R17

Transient Blade Row Methods With Pitch-Change Solve on Reduced Geometry

Full-wheel Model

ANSYS CFX transient pitch-change models Profile Transformation (PT)

Time Transformation (TT)

Fourier Transformation (FT)

Small/Moderate Pitch

Small/Moderate Pitch

Large Pitch

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Single Stage Multistage

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PT

Frozen gust Single Stage Multistage

TT

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Frozen gust Single Stage Multistage Blade Flutter

FT

Reduced Model

Transient interaction

Transient interaction + Correct blade passing frequencies

Transient Blade Row Methods ƒ Extended models and improved usability ƒ Time Transformation and Fourier Transformation ƒ Multi-stage, Asymmetric flow, Multi-disturbance

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Transient Blade Row with CHT Mixing plane improvements Convergence monitoring for cyclically periodic flow (ȕ) Harmonic Analysis: frequency-domain method (ȕ)

Transient Blade Row: TT for Multistage ƒ Modeling multistage with combination of TT and Single-Sided Time Transformation (STT) interfaces ƒ Flexibility in modeling multi-stage with combination of TT, STT and PT interfaces for wide range of machines ƒ Further improvement to aerodynamic performance prediction

Transient Blade Row: FT-TRS with Asymmetry ƒ Coupling single rotor passage to 360 domain with Fourier Transformation (FT) ƒ Handle single and multi-frequential disturbances ƒ Examples of large single disturbance Impeller in a vaneless volute

Compressor operating off-design - Fan in crosswind - Boundary layer ingestion - Ground vortex ingestion

ƒ Example of large multi-frequential disturbances Impeller in a vaned volute, with two disturbances seen by rotor 1) diffuser blade passing 2) one-per-rev variation due to volute

Transient Blade Row: FT Multi-disturbance ƒ Fourier Transformation (FT) with multiple disturbances ƒ Frozen gust analysis with inlet and outlet disturbances

Transient Blade Row: FT for Multistage ƒ Fourier Transformation (FT) with ƒ multiple pitch ratios ƒ multiple frequencies

ƒ All the benefits of FT method – now also for multi-stage analysis ƒ Incompressible fluids ƒ Large pitch ratio ƒ etc.

Transient Blade Row: with CHT ƒ Altered solid thermal response to combine CHT with TBR

Transient Blade Row: Usability ƒ Cyclic and polar plots in solver monitors (ȕ) ƒ Overlay multiple common blade passing periods ƒ Clear visualization of convergence to quasi-steady solution ƒ Visible beta feature

ƒ TBR restart with time-step size change ƒ Stop FT or TT and then resume with larger time step ƒ Reduce the overall simulation time required to reach convergence

Transient Blade Row: Harmonic Analysis (Ȗ) ƒ Introduction of frequency-domain method ƒ A priori specification of resolved frequencies Æ highest solution efficiency ƒ Advanced implementation with numerous advantages ƒ Truly non-linear, no shock smearing, …

ƒ Can be used with all existing pitchchange methods ƒ 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

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User Location (Surface) Output ƒ Results output to arbitrary surface locations ƒ Generate significantly less data ƒ Leaner simulation and analysis

ƒ Significant impact for large transient cases ƒ Data (disk space) may be reduced by orders of magnitude ƒ Less data sent between CFD-Post engine and GUI during post-processing

ƒ Analogous capability for Fluent and CFX

Arbitrary surface output location (independent of solver mesh)

Live CFX Solution Monitoring in CFD-Post (Ȗ) ƒ Building on “User Surface” output

FSI with CFX and Systems Coupling ƒ 2-Way FSI between CFX and Mechanical ƒ Supersede MFX with workflow and technology consistent with FluentMechanical coupling ƒ Initial support for steady and transient exchange of forces and resultant displacements

GENERAL PHYSICS MODELING

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Intermittency Transition Model ƒ One-Equation Intermittency-based Transition Modelling ƒ Significant advancement of the Ȗ-Reș model ƒ ƒ ƒ ƒ

Reduce number of equations Galilean invariant Simplified correlations Crossflow instability

Advances in Scale-Resolving Turbulence Modelling ƒ New Shielded Detached Eddy Simulation (SDES) ƒ Stronger shielding than Delayed DES ƒ Clear separation of RANS and LES mode ƒ New option for existing DES SST

ƒ New Stress-Blended Eddy Simulation (SBES) ƒ Incorporates and builds on SDES ƒ Faster switch to LES modes ƒ Combine RANS and LES, with blending (f) ƒ Currently using SST and WALE LES

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Æ Blended eddy viscosity

Q tSBES Q tRANS ˜ f SBES Q tLES 1  f SBES

USER ENVIRONMENT

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CFD-Post Charts of CFX Monitor Data ƒ Access to CFX monitor data for use in charts in CFD-Post ƒ Include convergence plots in reports generated with CFD-Post

Time Animation ƒ Ease-of-use for transient postprocessing ƒ ‘Music player’-like control ƒ Play/stop ƒ Next/previous time step ƒ First/last time step

ƒ Options to ƒ Specify desired transient range by time step, time, or crank angle ƒ Control which frame to use when between available frames ƒ Save time animation to movie file

GUI-Engine Communication Efficiency ƒ Avoid compression/decompression during data transfer ƒ Improve interactive efficiency/performance ƒ More data transferred ƒ But: no compression/decompression cost

R17 R16

Support for STL Surfaces ƒ Ability to import/export *.stl format geometry definition ƒ Define post-processing locations ƒ Import as contextual geometry ƒ Export any surface locator for other uses ƒ e.g. surfaces in Fluent

Original CAD geometry surfaces around flow domain brought in as STL to give improved context to simulation results