NASA Technical Reports Server (NTRS) 20140009170: Holistic Aeropropulsion Concepts

Holistic Aeropropulsion Concepts

NASA Aeronautics Research Institute

NASA Aeronautics Research Mission Directorate (ARMD)

2014 Seedling Technical Seminar

February 19-27, 2014

Principal Investigator: Vikram Shyam - GRC/RTT
Ali Ameri - RTT/OSU
Phillip Poinsatte - GRC/RTT
Douglas Thurman - RTT/ARMY
Dennis Culley - GRC/RHC
Peter Eichele - GRC/FTC
Sameer Kulkarni - GRC/RTT
Herb Schilling - GRC/VEO
Christopher Snyder - GRC/RTM
Surya Raghu - Advanced Fluidics LLC
Mike Zelek- GRC/FTC
Adam Wroblewski - GRC/RHI

a Langston 1980 |7J

c. Goldstein and Spores 1988 |8|

d. Wang et al. 1997 |9)

Fig. 1.5 Secondary flow field models from a. Langston (7], b. Sliarma and Butler [1],
Goldstein and Spores [8]. and Wang et al. [9].

(a) Sparrow hawk

(b) Tawny owl

Figure 3: Prepared bird wings used for the presentation of
the results

1

Outline

• Motivation

• Background

• Objectives

• Approach

— Biomimicry

-Autonomous Closed-Loop Flow Control (ACFC)

• Results

• Conclusions

2

NASA Aeronautics Programs

Conduct func
will produce innovative concepts,
tools, and technologies to enable
revolutionary changes for vehicles
that fly in all speed regimes.

Integrated
Systems
esearch Program

onduct research at an integrated
system-level on promising concepts and
technologies and explore/assess/demonstrate
the benefits in a relevant environment

Airspace Systems Program

Directly address the fundamental ATM
research needs for NextGen by
developing revolutionary concepts,
capabilities, and technologies that
will enable significant increases
in the capacity, efficiency and
flexibility of the NAS.

Aviation Safety Program

Conduct cutting-edge research that will produce
innovative concepts, tools, and technologies to improve
the intrinsic safety attributes of current and future aircraft.

Aeronautics Test Program

Preserve and promote the testing capabilities of
one of the United States’ largest, most versatile and
comprehensive set of flight and ground-based
research facilities.

FA Program Organization Structure

NASA Aeronautics Research Institute

Fundamental Aeronautics Program Office

Aeronautical
Sciences Project

Fixed Wing
Project

Rotary Wing
Project

High Speed
Project

Aeronautical Sciences (AS)

Enable fast, efficient design &
analysis of advanced aviation
systems from first principles through
physics-based tools, methods, &
cross-cutting technologies.

Fixed Wing (FW)

Explore & develop technologies
and concepts for improved
energy efficiency &
environmental compatibility of
fixed wing, subsonic transports

Rotary Wing (RW)

Enable enable radical changes
in the transportation system
through advanced rotary wing
vehicles concepts & capabilities.

High Speed (HS)

Enable tools &technologies and
validation capabilities necessary to
overcome environmental &
performance barriers to practical
civil supersonic airliners.

4

NASA Subsonic Transport System Level Metrics

technology for dramatically improving noise, emissions, & performance

NASA Aeronautics Research Institute

TECHNOLOGY

TECHNOLOGY GENERATIONS
(Technology Readiness Level = 4-6)

BENEFITS* **

N+1 (2015)

N+2 (2020")

N+3 (2025)

Noise

(cum margin rel. to Stage 4)

-42 dB

LTO NOx Emissions
(rel. to CAEP 6)

-okTA

-75%

-tsG7o

Cruise NOx Emissions
(rel, to 2005 best in class)

1 -70%

-80%

Aircraft Fuel/Energy Consumption 1
(rel. to 2005 best in class)

cr - 33 % "

-50%

~ -60%

* Projected benefits once technologies are matured and implemented by industry. Benefits vary by vehicle size and mission. N+1 and N+3 values
are referenced to a 737-800 with CFM56-7B engines, N+2 values are referenced to a 777-200 with GE90 engines

** ERA'S lime -phased approach includes advancing "long -pole" technologies lo TRL 6 by 2015
X C0 2 emission benefits dependent on life-cycle CO a per M J for fuel and/or energy source used

5

Outline

NASA Aeronautics Research Institute

• Motivation

• Background

• Objectives

• Approach

— Biomimicry

-Autonomous Closed-Loop Flow Control (ACFC)

• Results

• Conclusions

Sources of Performance Hits

NASA Aeronautics Research Institute

Fan Noise

Compressor Stall HPT cooling

losses

Leakage from
seals, tips

Low-pressure

compressor

Combustor -
Noise, Mixing.

LPT -Weight

Low Re problems
Noise from aft stages

http://en.wikipedia.0rg/wiki/File:Turbofan_operation_lbp.svg

7

Incidence, Low Re Problems

NASA Aeronautics Research Institute

Horseshoe

vortex

Incidence angle

(d) -20“

Separation due to
adverse pressure

8

Flow Control

NASA Aeronautics Research Institute

• F I o w co nt ro I atte m pted

- Requires power

- Local effects that could be detrimental elsewhere

- Cannot adjust to changing environment

- VGJs extensively researched

- Blowing into BL is common

• Design compromise by averaging over mission

• Noise reduction by blowing into wake costs 5% compressor
bleed - unacceptable

• Sensing of flowfield and thermal field requires sensors/power
- trades performance for weight and cost

Biomimicry

• Imitating Life

• Using natural multi-parameter multi-objective
optimization to solve aeropropulsion
challenges

— Get something for almost nothing

• Challenges

— Geometric/ fluid dynamic scaling
- Identifying relevant physics to incorporate

10

NASA Aeronautics

Institute

X (mm) X (mm) X (mm)

Tamai et al., “Aerodynamic Performance of a Corrugated Dragonfly Airfoil Compared with Smooth Airfoils at Low Reynolds Numbers”

Known Bio-inspired Solutions

stream wise
velocity (m/s)

(a) Sparrowhawk

(b) Tawny owl

100

80

60

40

20

0

-20

-40

-60

streamwise
velocity (m/s)

5.0 m/s

80

60

40

20

0

-20

-40

-60

Fish et al., “The Tubercles on
Humpback Whales’ Flippers:
Application of
Bio-Inspired Technology” .

100

60

i 20

Geyer et al., “Silent Owl Flight, Experiments in the
Aeroacoustic Wind Tunnel”

streamwise
velocity (m/s)

« -5000HI

CM

■I 1 . I

• • • k i ••••»» ♦

11

Harbor Seal

NASA Aeronautics Research Institute

12

Harbor Seal

PIV on vibrissae at U of Rostock. Witte et al. 2012. Figure shows Q-criterion

• 40% mean drag coefficient reduction over cylinder

• 90% reduction of unsteadiness

13

Outline

NASA Aeronautics Research Institute

• Motivation

• Background

• Objectives

• Approach

— Biomimicry

-Autonomous Closed-Loop Flow Control (ACFC)

• Results

• Conclusions

Objectives - Fundamental Aero

| NASA Aeronautics Research Institute

• Use a holistic approach to

— Achieve a fuel burn reduction of approximately 3%
- Achieve noise Reduction of at least 2 db

]

Through

a. Passive Biomimicry

b. Autonomous Closed-Loop Flow Control (ACFC)

• Biomimetics enables more aggressive design that will
benefit further from ACFC

• While many applications have been studied, infinite
possibilities remain

15

Outline

NASA Aeronautics Research Institute

• Motivation

• Background

• Objectives

• Approach
-Biomimicry

-Autonomous Closed-Loop Flow Control (ACFC)

• Results

• Conclusions

16

Biomimetic Features

• Achieve delayed separation like seal whisker at
High Re

• Achieve distributed wake like seal whisker

• Keep profile drag at or below baseline

• Keep pressure side flow largely unaffected to
increase lift/power

17

Biomimetic Concept

Institute

a

• Create span-wise pressure gradient on suction side using
span-wise undulations

• Push adverse gradient to valleys near trailing edge

• Trailing edge valleys occur at span-wise location of leading
edge peaks

Peaks transition to valleys at crown location

Amplitude based on LE
radius

Pitch from Seal Whisker

18

Feasibility Study of Biomimetic Concept

| NASA Aeronautics Research Institute

• Potential flow solutions using MATLAB to understand span-
wise pressure gradients

• Unsteady 3D CFD using Glenn-HT

- Cp distribution at various span-wise locations

- Average wake pressure-loss coefficient 10% chord
downstream of TE

- Multiple incidence angles

• Wind tunnel testing

- SW2 cascade facility

- Total pressure surveys at 10% chord downstream of TE

- Hotwire surveys at 10% chord downstream of TE

- Multiple incidence angles

Outline

NASA Aeronautics Research Institute

• Motivation

• Background

• Objectives

• Approach

— Biomimicry

—Autonomous Closed-Loop Flow Control
(ACFC)

• Results

• Conclusions

20

ACFC Concept

NASA Aeronautics Research Institute

Use suction at the hub to divert BL from horseshoe vortex region and deliver it to
regions of separation and TE. This needs to be accomplished without moving
parts or external power.

Three Components:

1 .

2 .

3.

Source for flow control

• Slot upstream of LE on hub

• Positioned for maximum suction

• Positioned for maximum secondary flow
reduction

Performance improvement

• Pulsed flow at TE and SS

• Spanwise distributed pulsing slots at TE
based on owl feathers.

Fluidic control of flow

• Diverters and pulsing fluidics

• Manages flow from and to components

21

Feasibility Study of ACFC

NASA Aeronautics Research Institute

• 3D unsteady CFD

- Suction slot upstream of horseshoe vortex saddle point

- 3D simulation of fluidic actuators

• Wind Tunnel Tests

- Trailing edge pulsing with hotwire survey

• Fluidic actuator testing using bench-top tests

- Demonstrate repeatable consistent control

— Demonstrate versatile control of single fluidic actuator
using input signals

]

• Models created using FORTUS 250mc

22

Fuel Burn Sensitivities

-25

NASA Aeronautics Research Institute

-20

-10% SFC Reduction

-15

% Fuel Burn
Reduction

Estimate based on
Phase 1 results -
LPT

Predicted
at start of
Phase 1

o

-5% SFC Reduction

-10

-20

% Engine Weight Reduction

» This was previous work for a 300 PAX aircraft
» Benefits might be slightly lower for N2A (7 67 class) aircraft

Contents

NASA Aeronautics Research Institute

• Motivation

• Background

• Objectives

• Approach

— Biomimicry

-Autonomous Closed-Loop Flow Control (ACFC)

• Results

• Conclusions

24

Biomimicry

Hanke et al., “Harbor seal vibrissa morphology suppresses vortex-induced vibrations”, The Journal of Experimental Biology 213, 2665-2672 © 2010

25

Bq$4Ip*"ip

Biomimicry - Seal Blade

NASA Aeronautics Research Institute

Rolls Royce VSPT

Seal Blade

Noise reduction
through wake
control

Cpt

0.623

'

0 000

Cpt

SINE_2_R_1 (40 degs.)
m 0.628

0 00 0

Fuel burn
reduction due to
elimination of
separation

Total pressure loss coefficient

Biomimicry - Performance Improvements

NASA Aeronautics Research Institute

Incidence tolerance over
wide range leads to fuel
burn reduction

50% improvement in
pressure recovery leads to
fuel burn reduction

0.25

-40 -30 -20 -10 0 10

Incidence angle

VSPT Seal 1 Seal 2 Seal 3 Seal 4

Loss Coefficient at +5°

27

Biomimicry - Seal Blade at 0° Incidence

NASA Aeronautics Research Institute

Separation

Shifts loading in
span-wise
direction to
prevent
separation.

VSPT Blade - no
modifications

28

NASA

'Autonomous Closed-Loop Flow Control

- ACFC

NASA Aeronautics Research Institute

29

ACFC - BL Suction

> 1 0% span
near hub has
improved
loading.

Weight

Reduction

eronautics Research Institute

tagnation press IPLOT3DJ
40 degrees

agnation press. (PL0T3D]
40 degrees Suction

No suction

horseshoe

With suction

ACFC - Fluidic Devices

NASA Aeronautics Research Institute

• Showed that for FI, repeatable consistent control is
possible

• If port 2 is closed, port 1 controls jet exit such that
flow always exits at 2 unless port 1 is closed

• If ports are both open, both control ports can be
used to switch flow

Control port 1 y Control port 2

Exit 1

Exit 2

\

Exit indicator

ACFC - Trailing Edge Pulsing

Testing in progress

SW-2 cascade

Numerical

for Flow Control. Gokoglu, Suleyman ; Kuczmarski, Maria ;
Culley, Dennis ; Raghu, Surya, 2011

Helmholtz sweeping fluidic device

New idea - testing in progress

Frequency independent of pressure ratio across

device

Advanced Fluidics Inc. device with rapid
switching. Inventor- Surya Raghu.
Frequency varies with pressure ratio and
geometry

32

32

ACFC - Concept Diagram

33

Combination of Biofoils and ACFC for

Higher Loading

• A slot upstream of the Leading edge at the hub for suction

• Plenum to remove incoming signals

• Fluidic network to direct traffic and manage frequency content

• Biofoils to manage separation and incidence tolerance as well as regulate passage
vortex and reduce noise

• Trailing edge slots with spanwise pulsing (adjacent slots pulse out of phase)

Institute

NASA Aeronautics

34

Outline

NASA Aeronautics Research Institute

• Motivation

• Background

• Objectives

• Approach

— Biomimicry

— Autonomous Flow Control

• Results

• Conclusions

35

a

Conclusions

| NASA Aeronautics Research Institute

• Feasibility of Biomimetic geometry shown for Fuel burn
reduction

• Feasibility of Autonomous Closed-Loop Flow Control concept
shown (waiting on TE pulsing results)

• Major benefit of this system is that no external power or
electronics is required

• The system self-adjusts to changing flow conditions.

• At least 3% Fuel burn reduction and 2db noise reduction are
possible

• More can be achieved by applying to fan, compressor,
airframe

36

m

Patents Pending

• Holistic system concept

- Endwall flow control

- Wake noise reduction

- Fluidic network concept

• Seal-type aerodynamic surface design

- Electric cables, helicopter rotors, tail, turbine engine components

- Parameters for optimization

• Helmholtz Fluidic switcher

• Porous owl-type aerodynamic surface

- Mimicking of owl wing using virtual airfoil - LE and porous flow

- Low noise fan using synthetic owl feathers

- Compliant wall for subsonic and supersonic flow control
• Novel flow visualization technique using water

control

37

Broader Applications

• Fan blades - wakes, geometry

- Owl type blades, porous blades

• Compressors - apply similar strategy for stall control

• Turbines

- Porous trailing and LE. Possible to make a breathing airfoil to eliminate
combustor tone?

• Combustor

- Use fluidic to eliminate tone at source

• Sensors and probes

• Real-time flow measurement and visualization

• Landing gear, struts

• Electrical cables

• External flow - Landing Gear, Struts, Road Signs

Institute

38

Path to Infusion

SI

• Raise to TRL 3 in Phase 2

- Include effect of rotation

- Apply biomimetics to fan and compressor blades

- Pulsed blowing for fan noise reduction

- Fabricate and test complete fluidic network on benchtop

- Test fluidic network within RR VSPT blade in SW-2

- CW-22 testing at matched Re and Mach

- Optimization of geometry using COMSOL/MATLAB/Solidworks

- Extend Seedless Velocimetry measurement methods

- Testing of biomaterials in SW-2, water table

• Elements are of interest to

- Fixed Wing - propulsion efficiency, acoustics

- Aerosciences - Flow Control, Novel measurement techniques

Institute

39

i

n

L

lASi

' J

Flow Visualization for Phase 2

NASA Aeronautics Research Institute

a

• Water table set up in SE-1 facility

• Instrumentation installed - XBOX Kinect, IR camera, scales for
depth measurement

• Further upgrades in progress

Inlet

Cascade

40

Dye Injection - Visible

[ NASA Aeronautics

Institute

IR camera view

Horseshoe

location

41

Infrared Flow Vis.

NASA Aeronautics Research Institute

Real-time Quantitative Flow Vis.

NASA Aeronautics Research Institute

Cascade

XBOX Kinect and projection system

43

Phase 2 Collaboration - External

NASA Aeronautics Research Institute

• Microsoft

• Harp technology

• Advanced Fluidics

• Georgia Tech

• Cleveland State University

• Marine Mammal Center, San Diego

• Cleveland Zoo

• GLBio

44

Building a Biomimicry Discipline

BIOMIMICRY 3.8

Corporate Biomimicry Sponsors

Sherwin

Williams,

ROSS

Parker

Biomimicry Operationalizes Sustainability

Acknowledgements

NASA Aeronautics

li&fehUsllI

Institute

• Trong Bui, Albion Bowers, Jennifer Cole (NASA
DFRC)

• Ali Ahmadi (Cal Poly, Pomona)

• Jim Heidmann, Gwynn Severt, Jerry Welch,
Michael Hathaway, Dennis Huff, D.R. Reddy,
Mark Celestina, Milind Bakhle (NASA GRC),
GVIZteam, Ed Envia, Brian Fite, Dan Sutliff,
Danielle Koch, Chris Miller, Colin Creager
(SLOPE team)

• Krish Ahuja (Georgia Tech)

46

NASA Aeronautics Research Institute

Seal Blade Flow Visualization

NASA Aeronautics Research Institute

VSPT - 0 incidence |R Setup Seal Blade - 0 incidence

48

Pressure Pressure

r

N

ASA

L

pr

/

ACFC Suction Results

NASA Aeronautics Rese.

(1- Stagnation press. [PLOT3D]‘)/[.293)
.0.800

0.000

(l-'Stagnation press. [PLOT3D]'>/(.293)
. 0.800

0.000

0 . 9 _

0 8_

0 6_

0 . 9 _

3 7

0 6_

With

Suction

Without

Suction

49

ACFC Prototype Demo

NASA Aeronautics Research Institute

50

Fluidic Tests

NASA Aeronautics Research Institute

51

Engine/Aircraft Sizing Primer

NASA Aeronautics Research Institute

• Engines can impact an aircraft’s fuel burn through 2 means

» Improved Efficiency (i.e., reduced SFC)

» Reduced Engine (Pod) Weight

• Efficiency improvements typically have greater impact on large,
long range aircraft

» 1 % SFC improvement = -1 .67% block fuel reduction (300 PAX)

» 1 % SFC improvement = -1 .33% block fuel reduction (RJ)

» 1 % SFC improvement = -1 .20% block fuel reduction (LCTR2)

(25% larger impact on Large Twin vs. Regional Jet, 40% larger vs. LCTR2)

• Engine weight reduction can also provide important fuel burn
savings as aircraft size increases

» 5% engine wt reduction = -1% block fuel reduction (300 PAX)

» 5% engine wt reduction = -0.6% block fuel reduction (RJ)

» 5% engine wt reduction = -0.5% block fuel reduction (LCTR2)

(57% larger impact on Large Twin vs. Regional Jet, twice [2x] vs. LCTR2)

• Turbofan engines on larger aircraft typically have higher bypass ratios which reduces weight
fraction of turbine blade/vanes, effect even more pronounced for turboshaft engines

NASA

/ Weight Breakdown on LCTR2 Advanced Engine

jpr “standard” 2-stage power turbine (PT)

NASA Aeronautics Research Institute

All turbines
(~1/4 of eng wt.)

Power Turbine
1 6% of eng
wt.

/ Weight Breakdown on LCTR2 Advanced Engine

4-stage Variable-Speed Power Turbine (VSPT)

NASA Aeronautics Research Institute

In turboshaft engines, Turbines are major weight components

All turbines
(-40% of eng
wt.)

Power Turbine
-31% of eng
wt.

Fuel Burn Sensitivities

NASA Aeronautics Research Institute

-25

0 -10 -20 -30

% Engine Weight Reduction

» This was previous work for a 300 PAX aircraft
» Benefits might be slightly lower for N2A (767 class) aircraft

Fuel Burn Sensitivities

NASA Aeronautics Research Institute

% Fuel Burn
Reduction

» This is for the LCTR2 baseline vehicle
» Shorter mission range reduces benefits seen from 300pax

Notional vehicle characteristics

NASA Aeronautics Research Institute

EIS = 2025 (2018
tech)

TOGW =89k Ibm

Payload = 90 pass.

Engine = 4x5,200
HP

Fuel = 9,500 Ibm

Range > 1,000nmi

Cruise > 300 knots

Cruise altitude
28k-ft

Cruise L/D * 12
Rotor tip speed
650 fps hover

Drawing / dimensions are from previous iteration, but are representative 350 fps cruise

NASA

LCTR “Design” Mission Profile (similar to Regional aircraft)

NASA Aeronautics Research Institute

Climb to cruise
altitude @ MCP

Cruise @ best range
velocity to mission range

3 min. idle,
Takeoff + 2 min.
hover (OGE)

> lOOOnm @ > 300 knots
(about 3 hours)

Convert to “airplane"
mode. Reduce rotors
to cruise rpm

+ 100 nm for
diversion

Descend at best range
velocity (no range credit)

+ 30 min. @

5,000 ft,

ISA+20° C

1 min. hover
OGE + landing

Mission is Climb/Cruise dominated =80% fuel

Modeled in NDARC — NASA Design and Analysis of Rotorcraft

Johnson, W„ “NDARC, NASA Design
and Analysis of Rotorcraft,” NASA TP
2009-215402, December 2009