Overview of CIRA participation in the Clean Sky GREEN REGIONAL AIRCRAFT (GRA) ITD Greener Aeronautics Symposium University of Glasgow - 3 November 2014 Raffaele Salvatore Donelli, PhD Centro Italiano di Ricerca Aerospaziale CSJU Seconded Project Officer
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Overview of CIRA participation in the Clean Sky GREEN ... · Greener Aeronautics Symposium – Glasgow - 3 November 2014 4 The G reen R egional A ircraft (GRA) ITD Regional market
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Overview of CIRA participation in the Clean Sky
GREEN REGIONAL AIRCRAFT (GRA) ITD
Greener Aeronautics Symposium University of Glasgow - 3 November 2014
Raffaele Salvatore Donelli, PhD
Centro Italiano di Ricerca Aerospaziale
CSJU Seconded Project Officer
Greener Aeronautics Symposium – Glasgow - 3 November 2014 2
Forewords
Clean Sky Green Regional Aircraft ITD
GRA Domains
New Configuration
Low Weight Configuration
Low Noise Configuration
Partial review of CIRA contribution
Green Regional Aircraft ITD
Overall scenario of Technologies & Demonstrations
Greener Aeronautics Symposium – Glasgow - 3 November 2014 3
The GRA ITD in the Clean Sky JTI
Eco-design For Airframe and Systems
Vehicle ITD
Tra
nsvers
e I
TD
for
all
veh
icle
s
Smart Fixed-Wing
Aircraft
Green Regional
Aircraft Green
Rotorcraft
Clean Sky Technology Evaluator
Sustainable and
Green Engines
Systems for Green
Operations
Leaders: Airbus
& SAAB
Leaders: Eurocopter
& AgustaWestland Leaders: Alenia
& EADS CASA
Leaders: Dassault Aviation
& Fraunhofer Institute
Leaders: Rolls-Royce & Safran
Leaders: Liebherr
& Thales
ITD: Integrated Technology Demonstrator
Greener Aeronautics Symposium – Glasgow - 3 November 2014 4
The Green Regional Aircraft (GRA) ITD
Regional market is a large part of Air Transport System: today, in
the world, 45% of flights are operated with regional aircraft.
In 2020 the share is estimated to rise to around 50%.
Substantial contribution to the “Clean Sky” shall then come from
the Regional Air Transport
Improvement of the environmental impact deriving from the
operation of regional aircraft are expected mainly from weight, drag
and noise reduction technologies, as well as from the integration of
advanced technologies belonging to other domains.
Greener Aeronautics Symposium – Glasgow - 3 November 2014 5
GRA High Level Objectives
To demonstrate technologies for future regional aircraft aiming at reducing:
fuel consumption/pollution
external noise
Ecolonomic Life Cycle
ACARE Goals
(CO2 & NOx reduction)
Aircraft Design Area Aerodynamics Structures&Materials Propulsion Power Requirements
Aerodynamics Flight Procedures Propulsion
Materials Design Concepts Standards & Rules
Green Perfomance
External noise
pollution & fuel consumption
Life Cycle
Greener Aeronautics Symposium – Glasgow - 3 November 2014 6
GRA High Level Work Program
Achievements of environmental targets through:
advanced aerodynamics and low noise design (Low Noise Configuration domain)
advanced structures and materials (Low Weight Configuration domain)
all electric aircraft architectures (All Electric Aircraft domain)
Greener Aeronautics Symposium – Glasgow - 3 November 2014 45
CIRA – Krueger Flap – Design Concept
Krueger Slat by CIRA - L/E device designed to greatly
enhance, combined with T/E flap, the wing high-lift
performance, so as to meet A/C low-speed requirements,
still preserving laminar flow on the wing upper side.
Very good high-lift performances were predicted by 3D CFD analyses,
confirmed by 2D WT tests, showing the ability of this device to delay
wing stall up to large angles of attack (≈13 deg), with a consequent
significant CLmax increase (≈ 0.5) wrt other HLD configurations.
The original designs of Krueger and T/E single-slotted flap were tailored by
ALA to the final GTF 130-seat A/C aerodynamic model; relevant 3D CFD
analyses in landing configuration
confirmed previous results, so as
the A/C low-speed requirements were
fully met. This architecture is the basic HLD
geometry brought to the final WT demonstration
on the complete A/C powered model (ESICAPIA).
FLOW
SEPARATION
SKIN FRICTION
@ POST-STALL
• = 14°
3D CFD
Greener Aeronautics Symposium – Glasgow - 3 November 2014 46
CIRA – Krueger Flap – 3D optimization
Automatic 3D Krueger shape-modification/positioning Automatic 3D flap shape-modification/positioning & droop spoiler rotation
CFD Analysis of initial configuration (flap separation)
Minimized flap separation after some
steps of optimization
Parametric CFD mesh (4 Mcells)
Greener Aeronautics Symposium – Glasgow - 3 November 2014 47
CIRA – Krueger Flap – 2D WT Tests
Krueger Slat + Single-Slotted Flap
As expected, 2D WTT confirmed numerical
analysis. Large increase in CLmax (≈ 0.5)
wrt other HLD and delay of the wing stall to
high angles of attack (≈13°)
SPLdB
f (Hz)
Krueger + S-S flap
baseline S flap
From 2D WT tests the airframe noise
spectra result comparable,
neglecting the peak at high
frequency, to those of the baseline
HLD geometry
Noise Impact
Aerodynamic Impact
Greener Aeronautics Symposium – Glasgow - 3 November 2014 48
CIRA – Fences – Design Concept
Fence type C
Fence type B
Fence type A
Reduction of flap side-edge vortex intensity and shear stresses: Flap side-edge noise reduction
Greener Aeronautics Symposium – Glasgow - 3 November 2014 49
grid particular
GRID FEATURES NO FENCES WITH FENCES
CELLS NUMBER ~1.60e+07 ~2.20e+07
TYPOLOGY UNSTRUCTURED UNSTRUCTURED
vortical flow structure side edge particular
CIRA – Fence for Flap– CFD/CAA
Greener Aeronautics Symposium – Glasgow - 3 November 2014 50
grid particular
CIRA – Fence for Flap– CFD/CAA
Contour plots of the turbulent kinetic energy for 2D sections extracted from the aerodynamic field of both baseline and side-edge fence configurations.
baseline side-edge fence
Greener Aeronautics Symposium – Glasgow - 3 November 2014 51
CIRA – Fence for Flap– CAA Results
The slotted fence reduces the noise efficiently (6-8dB).
Though slightly high noise appears among the frequencies up to 50 Hz.
Downwards microphone, 270o, 500m
Greener Aeronautics Symposium – Glasgow - 3 November 2014 52
Single slotted flap
without fence (C70)
C7A C7C C7B
Fence A Fence B Fence C Reference
00
CIRA – Fence for Flap– 2D WT Tests
Greener Aeronautics Symposium – Glasgow - 3 November 2014 53
CIRA – Fence for Flap– 2D WT Tests
Greener Aeronautics Symposium – Glasgow - 3 November 2014 54
with FENCE
2D WTT - SPL
Noise reduction detected from 2D WTT; noise sources localization
revealed fence effectiveness in reducing flap tip vortex intensity.
Device applied to the GTF 130-seat A/C WT model (ESICAPIA).
w/o FENCE
CIRA – Fence for Flap– Conclusions
Greener Aeronautics Symposium – Glasgow - 3 November 2014 55
CIRA – Morphed Flap – Design Concept
SACM Flap by UniNA - Smart Actuated Compliant Mechanism architecture, made up of
articulated ribs structure, actuated by an electric motor, enabling dual-morphing capability:
DESA Flap by CIRA - Deeply Embedded Smart Actuators
architecture, constituted by elastic cells connected each other
in a serial way along the flap chord; SMA actuators
contraction causes the relative rotation of the rib components.
•Mode #1
•2D Prototype
The morphed shape (mode #1)
will be tested on the complete
A/C WT model
(ESICAPIA).
Mechanical demo will be performed on a 1:1 (3.6m span) prototype
sized to the half (inner part) of the outboard flap
Mode #1: adaptive flap
camber (T-Off / Landing)
Mode #2: load control
tab (flap stowed)
•2D Prototype
Morphing Flap: Novel wing T/E device conceived to match a given
“target shape”, as an aerodynamically optimised cambered flap.
Two architectures have been developed:
Greener Aeronautics Symposium – Glasgow - 3 November 2014 56
CIRA – Morphed Flap– Design Concept
Optimized morphed flap geometry by CFD
2,7
2,8
2,9
3
3,1
3,2
3,3
3,4
3,5
0 1 2 3 4 5 6 7 8alfa
cl
baseline
best
Mechanical Concept
Greener Aeronautics Symposium – Glasgow - 3 November 2014 57
A mechanical prototype of a full-
size segment of the outboard flap
has been manufactured
and …
successfully tested …
demonstrating the functionality
and ability of the morphing flap
structure to match the target
shape, while withstanding
simulated aerodynamic loads.
CIRA – Morphed Flap – Prototype
Greener Aeronautics Symposium – Glasgow - 3 November 2014 58
CIRA – Morphed Flap – Prototype
Greener Aeronautics Symposium – Glasgow - 3 November 2014 59
SPLdB
f (Hz)
S-S flap
Morphed flap
Morphed Flap
the difference in terms of airframe noise between
original single-slotted (blue curve) and morphed (red
curve) flap shapes is negligible
Noise Impact
Results of 2D WT tests Vs numerical show an increment
in CL max (≈ 0.4) wrt the original single-slotted flap.
Nevertheless, the high-lift requirements are not fully met
because of low stalling angle.
Aerodynamic Impact
Single
Slot
Morphed
CIRA – Morphed Flap – 2D WT Results
Greener Aeronautics Symposium – Glasgow - 3 November 2014 60
GRA – Nose & Main Landing Gear
Nose
Landing Gear
Main Landing Gear
The first step was the design of MLG and NLG
baseline architectures, jointly carried out by
ALA and MBD.
Greener Aeronautics Symposium – Glasgow - 3 November 2014 61
CIRA – Nose & Main Landing Gear
The second step was the development of low-noise concepts, by GRA
Members and Partners of projects ALLEGRA, CALAS & NOISETTE,
through numerical studies (empirical predictions and
CFD/CAA analyses) and basic WT Tests as well.
The feasibility of relevant solutions
was assessed by ALA & MBD and
some modifications were applied,
when necessary.
The NLG down-selected concepts were:
#N1 Spoiler
by NOISETTE
#N2 Wheels
wind-shield
by NOISETTE
#N3 Wheels
hub-caps
by FHG #N4
Perforated
fairings
by
ALLEGRA
Greener Aeronautics Symposium – Glasgow - 3 November 2014 62
Greener Aeronautics Symposium – Glasgow - 3 November 2014 64
CIRA – Landing Gear – Acoustic devices
3. Fairing design
The CIRA fairing proposal consists of two separated covers that has been designed by complying with the preliminary considerations, the bay geometrical constraints and by not interfering with LG kinematics.
Cover applied on the main leg and on the absorber
Reduce high frequency of the smaller parts;
Reduce interactions between main leg and absorber. Hole cap applied on the leg joint
Attenuate the hole cavity tone.
Rough estimation of the noise reduction
ΔdB = 10log(1-Sf) ~ 3dB
Sf (fairing surface/LG surface)
A draw-back of the classical fairing is that the high speed flow deflection
onto other components and fairing itself can introduce additional noise
sources.
Making the fairing porous can lead to an additional noise decrease.
Porosity of about 40% is the right trade-off
Greener Aeronautics Symposium – Glasgow - 3 November 2014 65
Bay and Door Liners
The device proposed consist of a set of absorber materials applied on the fuselage at the aim of dissipating acoustic energy (bay and door). Acoustic liners are sandwich materials that consist of honeycomb closed by two sheet layers. The facing-sheet is micro-perforated. Liners can be tailored to dissipate acoustic energy at certain frequencies by changing the liner manufacturing characteristics. The radiation characteristics of the liner is defined by the acoustic impedance Z.
2DoF 1DoF
Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2
Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2
Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2
Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2Porous face sheet
Porous septum
Solid back-plateHoneycomb
h
h1
h2
CIRA – Landing Gear – Acoustic devices
Greener Aeronautics Symposium – Glasgow - 3 November 2014 66
CFD/CAA performed have showed that the
preliminary set of liner parameters for the
frequency of 300 Hz exhibits a modified SPL
directivity with an averaged SPL reduction of
1.3dB
CIRA – Landing Gear – Acoustic devices
Greener Aeronautics Symposium – Glasgow - 3 November 2014 67
GRA – Nose & Main Landing Gear
ALLEGRA Project
Tests on fulls cale Nose Landing Gear
Tests on Main Landing Gear – scale 1:2
Nose Landing Gear
In PininFarina WT
Greener Aeronautics Symposium – Glasgow - 3 November 2014 68
Other CIRA Activities
Synthetic Jet Simulation
Wind Tunnel Investigations on gap/step/roughness
effects on laminar flow
Drag Reduction (3D micro-riblets)
RANS solver development for open rotor simulations
Greener Aeronautics Symposium – Glasgow - 3 November 2014 69
LNC – Technologies & Demonstrations
WTT2 - NLF wind tunnel test investigation (high speed)
WTT8 - Gust Load Alleviation wind tunnel test investigation