unmanned aircraft system (uas) engine research at … motor; 30-60 mph, 1.9 kg total weight 82 kw...

UNCLASSIFIED

UNCLASSIFIED

UNCLASSIFIED

UNCLASSIFIED The Nation’s Premier Laboratory for Land Forces

Unmanned Aircraft System (UAS) Engine

Research at U.S. Army Research Laboratory

Dr. Mike Kweon

Engines Research Team Lead

VTD-Propulsion Division

U.S. Army Research Laboratory

Presented to:

Mech Aero 2015

(San Francisco, CA)

October 7, 2015 DISTRIBUTION STATEMENT A. Approved for public

release; distribution is unlimited.

UNCLASSIFIED


Why Unmanned Systems?

• Enhance situational awareness – ISR

– “Eyes of the Army”

• Reduce human workload

• Improve mission performance

– Persistence, versatility, survivability

– Ideal for dull, dirty or dangerous missions

• Minimize overall risk to human life

• Reduce cost

Multiple advantages to manned systems

2

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UAS Applications

rescue filming agriculture

Fire fighting Border control military

Selected UAS Application Areas

3

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U.S. DoD UAS Inventory

Fiscal Year

Nu

mb

er

of

UA

S [

un

its

]

2011 2012 2013 2014 2015 2016 20175000

5500

6000

6500

7000

7500

8000

8500

(Ref: DoD Report to Congress, 2012)

Dramatic increase over the last 15 years

Army: 48 (2001) >7500 (2015)

94.1%

4.2%0.4% 1.3%

UAS Usage (2015)

ARMY AF NAVY MC

4

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UAS Presidential Budget

(PB14)

$-

$500.00

$1,000.00

$1,500.00

$2,000.00

$2,500.00

RDTE PROCUREMENT OM

BU

DG

ET

[$M

]

CATEGORY

2014 2015 2016 2017 2018

RDTE: Research, Development, Test, and Evaluation

OM: Operations & Maintenance

Decreased budget trend for DoD UAS RDTE but global UAS

spending may double over the next decade (prediction)

(Ref: Unmanned Systems Integrated Roadmap FY2013-2038, 14-S-0553)

5

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Current Major Army UAS

100-500

15,000

20,000

29,000

Group 1 (0-20 lbs)

Group 3 (<1320 lbs)

Group 3 (<1320 lbs)

ISR

Alt

itu

de [

ft]

ISR/RSTA, C3, FP

ISR/RSTA, C3, Log, PS/TCS, FP

ISR/RSTA, C3, Log, PS/TCS, FP

0.208L 28 kW rotary engine

104-127 mph

25.3 kg total payload

170 kg MTOW

Electric motor; 30-60 mph, 1.9 kg total weight

82 kW 2x0.8L diesel engine

69/92-138 mph

227 kg total payload

884.5 kg MTOW

119 kW 2L diesel engine

81-155 mph

760 kg total payload

1633 kg MTOW

Endurance [hrs] 21 30 6 1-1.5

RQ-11B

RQ-7B

MQ-5B

MQ-1C

DoD designation

R: Reconnaissance aircraft

M: Multi-role

Q: Remotely piloted aircraft system

#: series number of the remotely piloted aircraft systems

Increased payload more power

More missions

Group 4 (>1320 lbs)

6

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UAS Future for the Army

Manned-UnManned Teaming (MUM-T) Technologies:

Merge air, ground, sea unmanned systems with

unmanned and manned systems

UAV Swarms

Needs:

• Runway independent vertical takeoff

• Easy to takeoff

• Longer endurance

• Equivalent speed to Apache

Needs:

• Interoperability

Increased mobility with small more agile

manned-unmanned systems

Teaming among Apache,

Gray Eagle, and Shadow

Parameter Unit Apache AH-64E Gray Eagle Shadow

Speed [mph] 165-177 81-155 104-127

Range [mi] 295 249 68

Endurance [hrs] ~3 30 6

Max altitude [ft] 21,000 29,000 15,000

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Problems

Hit

Crashes

Mechanical failures & Operator mistakes

What should we do?

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Areas for Improvements in

Propulsion & Power

• Reliability - #1 priority - survivability

– Reliable components / software

• Increased power - #2 priority - survivability

– Payload is being increased for electronic devices and weapons

• Longer endurance

– Needs to perform more missions

• Multi heavy fuel capability

– Reduce the logistic cost

– Engine technologies to operate on heavy fuels: F-24, JP-8, alt Jet fuels

• Reduced signature - susceptibility

– IR, noise, and smoke

– Signature detection and reduction technologies

• Increased speed

– To team with faster rotorcrafts such as Apache

Must be affordable!!!

9

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Small Engine Research

Facilities DoD Unique Small Engine Altitude Research Facility

Small Engine Comb Res Lab Small Engine Altitude Res Facility

Altitude: up to 25,000 ft (30,000 ft)

Temp: -40 to 130F

Power: 1 to 250 hp

Speed: up to 30,000 rpm

Single-cylinder

research engine

Optical

Opposed piston

engine

Fuel Spray Atomization Vaporization Mixing Combustion Power/Efficiency

Power: up to 302 hp

Torque: up to 535 Nm

Speed: up to 11,000 rpm

Thermal

10

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Multi Heavy Fuel Capability

• Extremely sensitive to fuel cetane number

– Insensitive to engine power except for the low CN fuels

– Knocking, noise, detonation reliability concerns

-30 -20 -10 0 10 20 30 40 50-10

0

10

20

30

40

50

60

70

CAD [°aTDC]

He

at

rele

as

e r

ate

[J

/ca

d]

Heat release rate: 3200 rpm/20%

CN30

CN35

CN40

CN45

CN50

CN55

Cool flame

-30 -20 -10 0 10 20 30 40 50-20

0

20

40

60

80

100

120

140

CAD [°aTDC]

He

at

rele

as

e r

ate

[J

/ca

d]

Heat release rate: 3200 rpm/40%

CN30

CN35

CN40

CN45

CN50

CN55

Pre injection

combustion

Premixed

phase Mixing

controlled

phase

Combustion Dependence on Fuel Properties

Premixed

phase

Mixing

controlled

phase

11

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Real Engine T & P at Fuel

Injection

0 10 20 30 40 50 60 70 80500

550

600

650

700

750

800

850

900

950

1000

In-cylinder pressure [bar]

In-c

ylin

de

r te

mp

era

ture

[K

]

pre injection

main injection

• Pre injection: between 10 and 17 bar and between 580 and 670 K Needs to prevent misfire and achieve optimal combustion at high altitudes

Pressures & Temperatures at Fuel Injections

10 bar/580 K

MAT cut at 40C

12

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Spray Combustion Research

Facility DoD Unique High-Pressure High-Temperature Chamber

Fuel Spray Atomization Vaporization Mixing Combustion Power/Efficiency

P: amb to 150 bar

T: 300 to 1000 K

O2 content: 0-21%

13

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T & P at Fuel Injection

0 10 20 30 40 50 60 70 80 90 100500

550

600

650

700

750

800

850

900

950

1000

In-cylinder pressure [bar]

In-c

ylin

de

r te

mp

era

ture

[K

]Measure Spray, Ignition and Combustion Processes

Spray A

CRC (SNL)

ARL

ARL_new

SNL

High Temp

Mid Temp

Low Temp

(1.00)

(1.05)

(1.11)

(1.18)

(1.25)

(1.33)

(1.43)

(1.54)

(1.67)

(1.82)

No visible combustion

14

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ID vs. Pressure

• Exponentially increased ID with decreasing pressure

• Lower CN fuel increases ID at lower pressures increased CN impact at high altitudes

2 4 6 8 10 12 14 160.5

1

1.5

2

2.5

3

Pressure [MPa]

Ign

itio

n d

ela

y [

ms

]

A-2

C-1

T=900K

Ignition Delay Dependence on Pressure & Fuel Property

15

Sea level

15k ft

25k ft

5k ft

10k ft

Higher altitudes

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CD vs. Pressure

• CD gets shorter at lower pressure and CN potentially higher EGT

2 4 6 8 10 12 14 16

2.5

2.6

2.7

2.8

2.9

3

3.1

3.2

3.3

Pressure [MPa]

Co

mb

us

tio

n d

ura

tio

n [

ms

]

A-2

C-1

T=900K

Combustion Duration Dependence on Pressure

& Fuel Property

16

Sea level

15k ft

25k ft

5k ft

10k ft

Higher altitudes

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Conclusions

• U.S. Army UAS dramatically increased over the last 15 years

• U.S. Army owns about 94% of all UAS aircrafts within the U.S. DoD

• Overall DoD RDTE budget is decreasing but the overall spending will

gradually increase.

• Global UAS spending is predicted to dramatically increase over the next

decade

• Current highest priorities include reliability, increased power, and longer

endurance within affordability

• Uncontrolled fuel property poses significant reliability concerns

• Needs for optimal engine design and calibration for high altitude

operation

17

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Acknowledgements

• ARL-VTP

– Michael T. Szedlmayer and Michael J. Tess

• AMRDEC AED

– Joseph Gibson, Ross H. Armstrong, Christopher A. Lindsey, Rik D.

Meininger, Newman B. Jackson, and Bernard Acker

• PM UAS

– Andrew V. Giddings, William G. Barnwell, Thomas P. Durgin, and Daniel F.

Dittenber

• General Atomics – Aeronautical Systems Inc

– Donald Sauder

18

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UNCLASSIFIED

Thank You!

unmanned aircraft system (uas) engine research at … motor; 30-60 mph, 1.9 kg total weight 82 kw...

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