Laser Induced Incandescence Diagnostic For Soot Measurements

Faculty Advisors

Dr. Pham1

Professor Dunn-Rankin2

Student Assistants

Michael Tran2

10/1/2009 NASA Grant URC NCC NNX08BA44A 1

1) California State University, Los Angeles, CA 90023

2) University of California, Irvine, CA 92697

PRESENTATION OUTLINE

• Soot Background• Diagnostic Techniques• Laser Induced Incandescence (LII)• My Research• Future Work

NASA Grant URC NCC NNX08BA44A 210/1/2009

3NASA Grant URC NCC NNX08BA44A

SOOT BACKGROUND

• Soot- Carbonaceous solid particles due to incomplete combustion

• Main constituents are carbon (97-99%%) and hydrogen (1-3%) by wt.

Individual Soot Particles 10-50nm

Soot Aggregates

Transmission Electron Microscopy (TEM)- Lund University)

10/1/2009

4NASA Grant URC NCC NNX08BA44A

Environmental and health aspects of soot• Contributes to 25% of global warming• Climate change• Particles < 1 micron can enter

human respiratory system

Benefits in soot• Carbon Black

• Tire industry• Ink

Air Pollution in Los Angeles, Time Magazine

SOOT BACKGROUND

10/1/2009

5NASA Grant URC NCC NNX08BA44A

DIAGNOSTIC TECHNIQUES

Probe techniques• Gravimetric Sampling• Disadvantage: Intrusive,

limited in spatial resolution and temporal response

Laser Diagnostics• Laser Induced Incandescence• Advantage: Non-intrusive• Disadvantage: Optical access

and expensive

Sampling Technique, Florida International University LIIScience.org

10/1/2009

6NASA Grant URC NCC NNX08BA44A

LASER INDUCED INCANDESCENCE

• Goal: Qualitative and quantitative measurement of soot• Output: Soot profile, soot volume fractions, and particle size• Principle:

– Soot is heated by laser (3500-4000K)– Incandescence flame images soot profile– Incandescence intensity soot volume fraction– Temporal decay of incandescence particle size

Laser Induced Incandescence, Lund University

10/1/2009

7NASA Grant URC NCC NNX08BA44A

LII THEORY

Lund University

10/1/2009

8NASA Grant URC NCC NNX08BA44A

TYPICAL LII COMPONENTS

Laser• UV to visible light (532nm) to IR

(1064nm)

Detector• ICCD Camera• Photomultiplier Tube

Soot Generator • Flame• Engine• Combustor

Lund University

Trigger Mechanism

• Function generator

Filter

• Filter range 300-600nm (400nm preferred)

10/1/2009

9NASA Grant URC NCC NNX08BA44A

MY RESEARCH

Goal• Compare sooting characteristics of neat and various blends of biodiesel to

diesel fuel in a diffusion candle flame and counter flow flame using Laser Induced Incandescence

10/1/2009

10NASA Grant URC NCC NNX08BA44A

EXPERIMENTAL SET UP

A

B C

D

E

F

G

H

I

J

K

A 532 Nd:Yag Laser

B Mechanical Iris

C/D Beam Steering Optic

E/F Cylindrical Lens

G Candle Flame

H 532nm Nd:Yag Dielectric Mirror

I 320nm Band-pass Filter

J ICCD Camera

K Beam Stopper

Photodiode (Not Labeled)

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11NASA Grant URC NCC NNX08BA44A

EXPERIMENTAL SET UP

Camera Control Unit

Oscilloscope

Function Generator

ICCD Camera

Photodiode

10/1/2009

12NASA Grant URC NCC NNX08BA44A

RESULTS AND ANALYSIS

Iso-octane Diesel Biodiesel

Flame images captured by hand-held digital camera

10/1/2009

13NASA Grant URC NCC NNX08BA44A

RESULTS AND ANALYSIS

Flame image of iso-octane captured by ICCD camera (No laser)

Laser induced incandescence of iso-octane captured by ICCD camera

Iso-octane Iso-octane

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14NASA Grant URC NCC NNX08BA44A

RESULTS AND ANALYSIS

Laser induced-incandescence images captured by ICCD camera

Iso-octane Diesel Biodiesel

10/1/2009

15NASA Grant URC NCC NNX08BA44A

RESULTS AND ANALYSIS

Flame intensity profile (incandescence)

Laser Induced incandescence profile

Note: Intensity not scaled

Iso-octane Iso-octane Diesel Bio-diesel

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16NASA Grant URC NCC NNX08BA44A

RESULTS AND ANALYSIS

Normalized intensity contour plot

Iso-octane Iso-octane Diesel Biodiesel (incandescence) (induced incandescence) (induced incandescence) (induced incandescence)

10/1/2009

FUTURE WORK

• Collect data holding constant flame height• Obtain quantitative measurement (soot volume fraction and particle size distributions)• Compare soot formation in diffusion candle flame versus counter flow flame

NASA Grant URC NCC NNX08BA44A 1710/1/2009

ACKNOWLEDGMENTS

• Grant provide by NASA # NNX08BA44A• Lasers, Flames, Aerosols Laboratory, UCI• Space Center, CSLA

NASA Grant URC NCC NNX08BA44A 1810/1/2009

QUESTIONS

NASA Grant URC NCC NNX08BA44A 1910/1/2009