Jet Engine Data Analysis

DARPA-funded experiments at United Technologies Research Center Hartford ConnecticutJet engine combustion instability - also occurs in turbomachinery

Thermo-acoustic instability; a periodic self-sustained oscillationInteraction between heat release rate and acoustics

Results in engine “Hooting” or “Howling” - audible toneOccurs at low equivalence (fuel-to-air) ratio !

Low ! is good for pollution - low NOx - and maintenanceHooting destroys the benefits

Periodically very high then very low temperaturesDescribe this mathematically using a model

Then look for a control approach1

Saturday, 5 November, 2011

Single-nozzle rigone combustor from a ring

measure pressuremeasure heat release rate

5,000 Hz sampling

Experimental Set-up

2

Theory - Rayleigh 1877Experiment - Rijke Tube 1859

- bunsen burner in an open tube with a wire gauze mesh

Heat into sound

Saturday, 5 November, 2011

0.2 0.22 0.24 0.26 0.28 0.3 0.32 0.34 0.36 0.38 0.4−8

−6

−4

−2

0

2

4

6

8

10

Time (s)

Pres

sure

(uni

ts)

Pressure signal

0.2 0.22 0.24 0.26 0.28 0.3 0.32 0.34 0.36 0.38 0.40

0.2

0.4

0.6

0.8

1

1.2

1.4

Time (s)H

eat r

elea

se ra

te (u

nits

)

Heat release rate signal

Experimental Data

3Saturday, 5 November, 2011

Data - pressure, log heat release rate

4

0.2 0.22 0.24 0.26 0.28 0.3 0.32 0.34 0.36 0.38 0.4−15

−10

−5

0

5

10

Time (s)

Pres

sure

(uni

ts),

Log

heat

rele

ase

rate

(uni

ts)

Signals

Saturday, 5 November, 2011

Model Structure

5Saturday, 5 November, 2011