2002 Rolls-Royce plcThe information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose other than that for which it is supplied without the express written consent of Rolls-Royce plc.

Whilst this information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of its subsidiary or associated companies.

Ref.ppt

Computational Fluid Dynamics

Engineering Simulation

Professor Peter Stow

RR Engineering Fellow – Computational Fluid Dynamics

Head of Aerothermal Methods

Rolls Royce plc

Design Considerations

Component GeometryComponent Geometry

AerodynamicsAerodynamics Heat TransferHeat Transfer

ManufactureManufacture

MaterialMaterial

WeightWeight

Stress LevelStress Level

VibrationVibration

Computer Aided Engineering

AERODYNAMICTHERMODYNAMIC

DESIGN

AERODYNAMICTHERMODYNAMIC

DESIGNCADCAD TEST

TESTMECHANICAL

DESIGNANALYSIS

MECHANICALDESIGN

ANALYSISMANUFACTURE

MANUFACTUREPRODUCT

PRODUCT

CFDMODELS

CFDMODELS

STRESSVIBRATION

MODELS

STRESSVIBRATION

MODELS

MANUFACTURINGPROCESSMODELS

MANUFACTURINGPROCESSMODELS

High Performance Computing Potential Impact

Reduced engineering analysis time & cost– more automated analysis

– more integrated analysis Improved accuracy of engineering analysis

– more accurate numerical model

– more accurate mathematical model of physical processes– achieved at acceptable cost– achieved in acceptable elapsed time

Advances in computers mean that this is becoming possible

CFD Applications

Combustion Two-Phase Combusting flow

external aerodynamics

fuel injector and combustercooling flows

Exhaust afterbody flow nozzle, mixer, jet flow

Turbine multistage aerodynamics

aero design and optimisation

end wall and blade heat transfer

film cooling

rotor shroud leakage

rim seals

unsteady vane/rotor flow

forced response

Engine Systems rotating disc cavity flows brush and labyrinth seals secondary air system losses

Nacelle aerodynamics crosswind effects installed engine/pylon/wing interaction

Fan aerodynamics fan flutter fan/OGV/pylon interaction IGV forced response

Compressor Multistage aerodynamics unsteady rotor/stator flow annulus leakage flow

Swept Fan Aerodynamics

Swept FanConventional Fan

Shock moreoblique, withlower losses.

Leading edgeswept rearwardsFlow

Leading edge

Shock (more radial)

Mn rel

Reduced axialvelocity at tip giveslower Mn and highblade angles

Fan Flutter - Issues

Fan Flutter

5% Margin required (before threats)

3% Stability Margin (after stack-up)

No Flutter post Bird-strike

Intake:- Acoustics- Inlet Distortion- Non-axisymmetry

Fan blade shape: - Aerodynamics- Untwist- Modeshape

Tip leakage & Treatment

Downstream Non-axisymmetric issues(pylon, reverser etc.)

Acoustic Liners

Fan Internal & Disk:- Mistuning- Damping

Downstream Acoustics

L/E Shape & Erosion

Engine-to-engine Variability

Fan Flutter

Aerodynamic Damping

unstable

Unsteady

Fan Flutter - Non-linear vs. Linear Unsteady

-0.1000

0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.8000

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

Interblade phase angle

log

decr

emen

t

C113 AU3D

C113 SLiQ

unstable

stable

• Steady Viscous Flow

• Unsteady Linearised Flow

• Vibration Modeshape from SC03

Steady

SC03 Mode

stableSurface Work

Fan-OGV-Pylon Design

StaticPressure

Fan-OGV-Pylon Design

Pylon field transmitted through vanes

-0.1

-0.075

-0.05

-0.025

0

0.025

0.05

0.075

0.1

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

Circumferential angle

Pylo

n ge

nera

ted

pertu

rbat

ion

uniform (datum) vanes

nonuniform vanes (5 types)

top dead centrepart overcamber

full-overcamber

datum

part undercamber

full undercamber

full overcamber

datum

full undercamber

part overcamber

part undercamber

Circumferential variation in vane type

Fan-BOGV-Pylon Interaction

Fan-BOGV-ESS Interaction

Body force

Body force

Determ

inistic stress Determ

inistic stress

Inlet boundary conditions

Inlet boundary conditions

Exit pressure

Exit pressure

PV

M m

essages

PV

M m

essages

MULTISTAGE ANALYSIS

Unsteady Rotor-Stator Interaction

Contours of Vorticity

3D Rotor-Stator Interaction

Turbine Forced Response

Turbine Forced Response

Wake Shaping

Original Wake P0

Shaped Wake P0

Engine Intake Analysis

Installed Nacelle Ground Plane Effects

25 Knot Forward Speed 35 Knot CrosswindNon-Dimensional Mass Flow = 2307 (full scale)

Freestream P = 380kPa T = 298K Driving P = 292kPa

25 Knot Forward Speed 35 Knot CrosswindNon-Dimensional Mass Flow = 2312 (full scale)

Freestream P = 380kPa T = 298K Driving P = 294kPa

Horizontal Cross SectionWindward Lip

Horizontal Cross SectionWindward Lip

25 Knot Forward Speed 35 Knot Crosswind Windward Lip Separation

25 Knot Forward Speed 35 Knot CrosswindNon-Dimensional Mass Flow = 2307 (full scale)

Freestream P = 380kPa T = 298K Driving P = 292kPa

25 Knot Forward Speed 35 Knot CrosswindNon-Dimensional Mass Flow = 2312 (full scale)

Freestream P = 380kPa T = 298K Driving P = 294kPa

Fan Face Plane Fan Face Plane

25 Knot Forward Speed 35 Knot Crosswind Windward Lip Separation

Engine Intake Analysis

Installed Nacelle Analysis

1,930,378 Tetrahedral Cells316,303 Points91,316 Boundary Faces

Inviscid Flow Solution:

Pictures: Visual3

Solution on Chordwise Cut through Inboard Nacelle

Flow Solution on Aircraft Surface - Fuselage, Wing, Nacelles and Pylons - Half Model

Installed Nacelle Analysis

Traditional 3D Design by Analysis

1st Design

2nd Design

nth Design

Original Design

AnalysePrepare next 3D CFD runSubmit o/night runWait for results

Continue sequence

AnalysePrepare next CFD runSubmit o/night runWait for results

2-D design toolsCloningstacking

FAITH Design System

Seven Perturbations

Automatic creation of perturbations and CFD submission for overnight runs

No Communications No Communications No CommunicationsNo Communications

FAITH - 3D Forward Linear Design

2nd Re-design(= nth design incurrent process)

OriginalDesign

Check linear design withovernight CFD run

Linear Design

Linear Design

Linear Design

Interactive day-time analysis

45

55

65

75

85

95

105

0 25 50 75 100 125 150 175

Axial Distance (mm)

Sta

tic P

ress

ure

/kp

a

FAITH - 3D Inverse Linear Design

2nd Re-design(= nth design incurrent process)

OriginalDesign

Check linear design withovernight CFD run

Original

Linear Design

User defined target flow field

Interactive day-time analysisNo need to iterate

Target

Non-Axisymmetric Endwalls

Application Areas(Whole Engine Modelling)

Aerodynamic Requirements:Performance

Efficiency (SFC)Surge Margin

Noise

Mechanical Requirements:Maximum Stress

F.O.D.

Manufacturing Processesand Cost

Weight

Aeroelasticity:Force Response

Flutter

Shape Optimisation Life

Heat-transferCooling

Rolls-Royce SOPHY Design System

PADRAM-HYDRA-SOFT Aerodynamic Design System Advance Parametric design system – R-R business application focus

– Turbomachinery blading

– Fan – BOGV - pylon

– Intakes

– By-pass Exhaust nozzle & afterbody

– Fan tone noise, Fan-BOGV noise

– Water-jet pump Direct links to CAD system(s) - Parametric representation Rapid automatic meshing – structured, unstructured, mixed grids State of the art versatile Optimisation system for design capability

Integrated Automatic Design Optimisation System

SOPHY: SOFT-PADRAM-HYDRA

Base desig

n

SOFT

HYDRA

PADRAM

Costconstraint

s

jm56

jm52

Design Review

OK?

New design

Yes

No

Optimum design

Convergence history

Design parameters

Optimizer

Additional design

parameters/cost

Automation Flowchart Geometry created & meshed parametrically CFD boundary conditions and mesh pre-processed in batch Costs and constraints extracted in batchLibrary of optimisers available

Current Design System

PADRAMHYDRASOFT

LPC System OGV pre-diffuser

Casingtreatment

Nacelle/Intake

Exhaustnozzle

Water pump

Nozzle design

Multi-stage design

Non axi- endwalls

Forced response

Nacelle Automation and Optimisation

SOFT GEMO

HYDRAJL09-PAX

JM52

Design Parameters

cost and constraint functions

mesh(RAMIN)RAMIN(Mesh)

Nacelle/Intake Design Space

The Design parameters – 77 parameters:• Intake Scarf Angle• Intake Centreline Angle (relative to engine centreline)• ……..

Secondary geometric parameters :• Internal Lip Tilt (angle between intake C/L and local lip

axis topline, sideline and bottom line)• Non-planer Highlight

scarf angle: +10 deg

+10°

2200200

RAMIN: Rapid Meshing for Intakes/Nozzles

RAMIN Mesh on Symmetry Plane

HYDRA solution

New Design Capability

PADRAMHYDRASOFT

Low noise fan and OGV design

Automatic design of

Casingtreatment

Parametric Exhaust Nozzle

System

General Endwall design capability

Parametric Collector box

Internal cooling

passages

Rotorperformance

StatorPerformance Pylon

Inletdistortion

Noise:

ToneBroadbandBuzzsaw

Under platform Cavity Well

design

High Performance Computing Potential - New Simulations

Cheaper/more affordable computing offers vast prospects for new

simulations Multistage Analysis - Steady/Unsteady CFD

– Component optimisation over whole operating range

– Whole engine optimisation Aeroelasticity - CFD <-> Stress/Vibration analysis

– Component optimisation for performance & structural integrity Noise Analysis - Unsteady CFD

– Design optimisation for Noise as well Performance & Stability Turbine Heat Transfer -CFD<->Heat Conduction<->Stress Analysis

– Performance & life optimisation Multi-disciplinary Optimisation

– CFD<->Structural Analysis<->Manufacturing Turbulence & Transition modelling

– Direct/Large Eddy Simulation

Turbulence & TransitionDNS & LES

Tone Noise Sources and Propagation

Distortion NoiseFull 3D Non-linearUnsteady

Buzz-SawFull AnnulusNon-Linear

Rotor AloneNon-LinearSteady

Fan/OGVOGV Geometry Fan/OGV Ratio

Bypass3D Bypass Liner/Geometry Optimisation

Radiation and Transmission Thru’ Shear Layer

RadiationIntake LinersIntake Geometry

LP TurbineMulti-stageUnsteady

Broadband Noise Sources

Rotor BBSelf-Noise Interaction with Inlet B.L.

Fan Wake/OGV Interaction OGV Self Noise

Jet Noise

Fan-OGV BB Sources due to turbulence interacting with (blade) surfaces

Jet Noise due to Turbulence (and shocks)

Low Tone Noise Fan Blade Design

HYDRA, PADRAM and SOFT used to demonstrate low tone noise fan blade design optimisation

~ 9dB reduction

Cost Function (Pa)

Design space covered axial and circumferential movement (lean & sweep) of blade sections over outer 20% of blade span (4 design parameters)

Design Iterations

datum cost

Each iteration around 2 hours on PC cluster initial optimum achieved in ~ 2 days

~ 75% span ~ 75% span

~ 95% span ~ 95% span

Low Tone Noise Fan Blade Design

Datum fan blade Low tone noise blade

Design optimisation introduces forward sweep of blade sections over outer 20% of span - leads to swallowed shock at tip compared to expelled shock of datum blade

contours of static pressurecontours of static pressure

Hydra QTD Buzz-Saw Analysis

26 blade full annulus Measured Static Stagger Angle Variation

Hydra CFD mesh ~55M nodesRun time per aerodynamic point (96 cluster CPUs) ~ 10 days

Viscous end wallsRotor tip gap includedAcoustic Liner included

Acoustic Liner

Broadband Jet Noise

Plane Jet DNS Far-field Noise

by Acoustic Analogy

Exhaust Nozzle LES

2002 Rolls-Royce plcThe information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose other than that for which it is supplied without the express written consent of Rolls-Royce plc.

Whilst this information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of its subsidiary or associated companies.

Ref.ppt

Computational Fluid Dynamics

Engineering Simulation

Professor Peter Stow

RR Engineering Fellow – Computational Fluid Dynamics

Head of Aerothermal Methods

Rolls Royce plc