ラジカル自発光とラジカル自発光とラジカル自発光とラジカル自発光と

その計測その計測その計測その計測

ラジカル自発光とラジカル自発光とラジカル自発光とラジカル自発光と

その計測その計測その計測その計測

燃焼工学講座燃焼工学講座燃焼工学講座燃焼工学講座　　　　 赤松赤松赤松赤松 史光史光史光史光

Spectrum of flame luminosity

Non-luminous Flame

11.4 mm

Direct photograph of the Bunsen flamewith the measurement point of MICROand electro-static probe

Spectrum of flame luminosity

Luminous Flame

OH and CH chemiluminescences are emitted in thedeactivation course (2) of OH* and (4) of CH*produced from the reaction (1) and (3), respectively.

CH + O2 ---> CO + OH* (1) OH* 　　　　 ---> OH + h νννν (2)

C2 + OH ---> CO + CH* (3) CH* 　　　　 ---> CH + h νννν (4)

where the superscript * denotes an excited state, h isthe Plank’s constant, and νννν is the frequency of thechemiluminescence.

OH and CH radical chemiluminescences

Direct photograph of Bunsen flame withmeasurement point

11.4 mm

Single-lens optics for point measurement

Paraxial Approximation, Gaussian Lens Equation

S1 S2

S1 S2

In Typical Case,S1 S2

S1S2For Example, , Then

f0: Focal Length

Control Volume

可視域可視域可視域可視域 紫外域紫外域紫外域紫外域赤外域赤外域赤外域赤外域

OH* 306.4 nm

CH*　 431.5 nm

C2*516.5 nm

Convex Lens

Concave + convex mirrors

Conventional method

Newly proposed method

Chromatic aberration of optics

1f0

= (n−1) 1r1

− 1r2

�

� �

�

� �

Refractive index and focal lengthas functions of wavelength

Typical aberration of point measurement optics

DL=50mm, f0=150mm

S2opt = 285.1 mm

近軸公式では

at Wave Length for Lens Design, λ λ λ λ = 546.1 nmSpherical Aberration

Chromatic Aberration

Rays passing through outer portion of lens are focused closer to the lens.

The shorter the rays' wave length, The shorter the focal length

Paraxial App. GLE

S2opt = 257.4 mmat OH-radical Wave Length, λ λ λ λ = 310 nm

S2 = 300 mmRay-Tracing Method

T i l Ab i f P i

Dpopt

Control volume

285.1

Pinhole

S2opt

’300260

Ray-Tracing Method

Y

mm

Y mm

(light wave length for the lens design: 546.1nm)Circle of Least Confusion

Optimum pinhole location and diameterusing ray-tracing method (DL=50mm)

Optimum pinhole location and diameteras functions of lens diameter

546.1nm

310nm

opt

S2op

t

Wave Length for Lens Design

OH-radical Wave Length

285.1

257.4

300

Optimum pinhole location and diameteras functions of wavelength

Single-lens optics and Cassegrain optics

Single-Lens Optics

Cassegrain Optics

Control Volume

Control Volume

MICRO probe

Front viewFront viewFront viewFront view Side viewSide viewSide viewSide view

Bird eyeBird eyeBird eyeBird eye’s views views views view

Multi-color Integrated CassegrainReceiving Optics (MICRO)

Cassegrain optics

Sperical aberration of single-lensand Cassegrain optics

Single-Lens Optics Cassegrain Optics

Estimation method of point measurementoptics and distribution of collection rate

Collection Rate G = Solid Angle of OpticsTotal Solid Angle (4π)π)π)π)

G

Direction to Optics

Pinhole

Control volume

Estimation Method of Point Measurement

= Total Rays Rays collected onto Pinhole

Collection rate distributions ofsingle-lens and Cassegrain optics

Measured collection rate distributions

Light detection system of Cassegrain optics

紫外光透過コア径200

for UV, Core Diam. 200 µµµµm

Control volume

OH C2(0,0)

488 nmCH

C2(0,1)

New Light detection system of Cassegrain

・・・・No Chromatic Aberration　　　Consisting of only mirrors

・・・・Minimum Spherical Aberration　　　Optimization of two mirrors’ curvature combination

・・・・Very High Light Collection Rate　　　Large diameter optics can be available due to elimination of spherical aberration.

・・・・Short Control Volume Length Along Optical Path　　　Minimum spherical aberration and masking effect of the center of convex mirror

・・・・Easy Alignment of Optics　　　Control volume can be visualized

Advantage of the MICRO system

Direct photograph of Bunsen flame withmeasurement point

11.4 mm

Ion current is produced from the followingreactions.

CH + O ---> CHO+ + e- (1) CH + C2H2 ---> C3H3

+ + e- (2)

OH chemiluminescence is emitted in the deactivationcourse (3) of OH* produced from the reaction (4).

CH + O2 ---> CO + OH* (3) OH* 　　　　 ---> OH + h νννν (4)

where the superscript * denotes an excited state, h isthe Plank’s constant, and νννν is the frequency of thechemiluminescence.

Ion current and OH chemiluminescence

Time-series signals of ion current obtained by electro-static probe, and OH chemiluminescence obtained byMICRO and single-lens optics

100

200

300

400

Ion

n

A

0

50

100

150

200

0

10

2030

40

0 10 20 30 40 50 60 70 80 90

Time ms

400

600

800

1000

0

100

200

300

0 50 100Time ms

Time-series signals of OH radical chemiluminescence bythe MICRO and ion current by the electro-static probe

CLx

x

PMMSPMCH

PMOH

FMSP

FOH

FCH P

PDM1

DM2

DM: Dicroic mirror PM: Photomultiplier F : Optical filter CL : Collection lens P : Pinhole

Light guide

CL

x-x

4mm

2mm

Previous point measurement system

Example of MICRO Application

MICRO

Mirror

Interference filter

Burner port

Cylindrical lens

Optical fiber cable

Pulse delay generator

Lens

Extension tube

Image intensifier

CCD camera

V/V amp.

Low pass filter A/D

PC

Detection unit

Argon-ion laser

PC

I/V OH I/V CH I/V MS

0

10

20

30

0

100

200

0

50

50 55 60Time ms

t=55.2 ms t=56.1 ms t=57.0 ms t=57.9 ms t=58.8 ms

15

85

Simultaneous measurement with images

Rayleigh scattering measurement

Photograph of experiment

Measurement of spectrum

Fiber (φφφφ=0.1mm)

50mm

Fiber

(φφφφ=0.1mm,N.A.=0.2)

r

z

Cassegrain Optics

Nozzle burner(φφφφ10mm)

Grating

CCDI.I.

Mirror

Processor PC

Fiber

MonochromatorMonochromator

Spectrum of flame luminosity

Wavelength (nm)

Emis

sion

inte

nsity

(rela

tive)

300 350 400 450 5000

1 CassegrainFiber

Change of spectrum with location

Wavelength (nm)

Emis

sion

inte

nsity

(a.u

.)

300 350 400 450 500

0.730.760.78

r/R=CH4-air

premixed

OH*(0,0)

CH*(0,0)

C2*(0,0)

C2*(1,0)

1E4

0

Wavelength (nm)

Emis

sion

inte

nsity

(a.u

.)

300 350 400 450 500

0.810.840.9

r/R=1E3

Change of spectrum with location

0.7 0.8

0.8

1

r/R

Emis

sion

inte

nsity

(rela

tive)

0.5 1 1.50

0.5

1

OH*(0,0)CH*(0,0)C2*(0,0)

Unburned

Burned

Locations of chemiluminescence intensity peak

Wavelength (nm)

Emis

sion

inte

nsity

(a.u

.)

300 350 400 450 500

0.91.11.21.3

OH*(0,0)

0

1E4CH*(0,0)

C2*(1,0)

C2*(0,0)

CH4-air premixed

φ=

Change of spectrum with equivalence ratio

Emis

sion

inte

nsity

(rela

tive)

0

1

(4,3)(3,2)(2,1)(1,0)(1,0)Band

Equivalence ratio

Em

issi

onin

tens

ity(re

lativ

e)

0.9 1 1.1 1.2 1.3 1.4

(0,0)Q(0,0)Q(1,1)R(1,1)QBand

OH

Em

issi

onin

tens

ity(re

lativ

e)

(0,0)Band

CH*

C2*(1,0)

(a)

(b)

(c)

Equivalence ratio

Emis

sion

inte

nsity

(rela

tive)

0.9 1 1.1 1.2 1.3 1.4 1.50

1

(1,1)(0,0)(0,0)Band

C2*(0,0) (d)

Change of peak intensity with equivalence ratio

Equivalence ratio

Emis

sion

inte

nsity

(rela

tive)

0.9 1 1.1 1.2 1.3 1.4 1.510-1

100

101

C2*/CH*C2*/OH*OH*/CH*

CH4/Air Premixed

Single-lens optics for point measurement

425 430 435

0.91.11.21.3

CH*(0,0)Q

(2,2)R

Emis

sion

inte

nsity

(a.u

.)

305 310 3150

1E4OH*

(0,0)R

(0,0)Q

(1,1)R

(1,1)Q

Wavelength (nm)

Emis

sion

inte

nsity

(a.u

.)

465 470 475

(5,4) (4,3)

C2*(1,0)1E4

0

(2,1)(3,2)

(1,0)

CH4-air premixed

Wavelength (nm)505 510 515 520

(1,1)

C2*(0,0)

(2,2)

(0,0)

φ=

Change of spectrum with equivalence ratio

Measurement of time-series spectrum

Multi-point measurement