Abstract

A new method for flame temperature measurement has been developed involving measurement of radiation, emitted by flames, in a narrow wavelength interval within the ultraviolet OH emission band. The mean value of flame emissivity within the wavelength interval is evaluated by measurement of mean flame transmission for a continuous spectrum source. The method requires that the wavelength interval studied be so narrow that the emission of the source used for transmission measurement and that of a blackbody at flame temperature both be approximately constant over the interval.

The method has been tested on steady flames over temperature ranges from 2000°K to 3000°K and excellent agreement obtained with sodium line reversal measurements. Temperatures of pulsed flames have been determined from photographic traces obtained with a monochromator-photo-multiplier-oscilloscope-camera combination. Two high speed light choppers were used, one to interrupt the radiations entering the monochromator and the other to interrupt, at a different frequency, the radiations from a hydrogen discharge lamp transmitted by the flame to the monochromator. The time resolution was 0.10 millisecond and the accuracy in temperature measurement about 40°K in the range 2000°K to 3000°K. The method was calibrated by means of sodium line reversal although it is easily adaptable to absolute calibration.

© 1951 Optical Society of America

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References

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  1. G. H. Dieke and H. M. Crosswhite, “The Ultra-Violet Bands of OH,” , (Nov.1948).
  2. H. G. Wolfhard and W. G. Parker, “Combustion Processes in Flames, Part VI,” Royal Aircraft Establishment; , (March1949).
  3. Supplied by National Technical Laboratories for use in the Beckman Spectrophotometer.

Crosswhite, H. M.

G. H. Dieke and H. M. Crosswhite, “The Ultra-Violet Bands of OH,” , (Nov.1948).

Dieke, G. H.

G. H. Dieke and H. M. Crosswhite, “The Ultra-Violet Bands of OH,” , (Nov.1948).

Parker, W. G.

H. G. Wolfhard and W. G. Parker, “Combustion Processes in Flames, Part VI,” Royal Aircraft Establishment; , (March1949).

Wolfhard, H. G.

H. G. Wolfhard and W. G. Parker, “Combustion Processes in Flames, Part VI,” Royal Aircraft Establishment; , (March1949).

Other (3)

G. H. Dieke and H. M. Crosswhite, “The Ultra-Violet Bands of OH,” , (Nov.1948).

H. G. Wolfhard and W. G. Parker, “Combustion Processes in Flames, Part VI,” Royal Aircraft Establishment; , (March1949).

Supplied by National Technical Laboratories for use in the Beckman Spectrophotometer.

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Figures (6)

Fig. 1
Fig. 1

Blackbody curves illustrating errors in temperature evaluation by the OH method.

Fig. 2
Fig. 2

Diagram of experimental apparatus for measurement of flame temperature.

Fig. 3
Fig. 3

Spectrogram of air-gas flame, showing region of OH spectrum used in determining flame temperature.

Fig. 4
Fig. 4

Comparison of OH method to sodium line-reversal method.

Fig. 5
Fig. 5

Film trace for pulsed flame.

Fig. 6
Fig. 6

Temperature record for one pulse of a gas-oxygen flame.

Tables (1)

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Table I Sample error calculation.

Equations (21)

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R = E J ,
A = E .
A = ( I 0 - I ) / I 0 ,
J = I 0 R / ( I 0 - I ) .
J d λ = [ I 0 R / ( I 0 - I ) ] d λ ,
J ¯ d λ = I 0 d λ R d λ / ( I 0 d λ - I d λ ) ,
Ē = λ 1 λ 2 E h T S d λ ÷ λ 1 λ 2 h T S d λ ,
J ¯ = λ 1 λ 2 J E T S d λ ÷ λ 1 λ 2 E T S d λ ,
h ¯ = λ 1 λ 2 h E T S d λ ÷ λ 1 λ 2 E T S d λ ,
H 0 = G λ 1 λ 2 h T S d λ ,
H F = G λ 1 λ 2 h ( 1 - E ) T S d λ .
( H 0 - H F ) / H 0 = λ 1 λ 2 E h T S d λ ÷ λ 1 λ 2 h T S d λ Ē .
F = G λ 1 λ 2 J E T S d λ ,
J ¯ = ( h ¯ G / G ) · F / ( H 0 - H F ) .
ln J + 5 ln λ = ln C 1 - C 2 / λ T .
Δ J / J + 5 Δ λ / λ = ( C 2 / λ T ) ( Δ λ / λ + Δ T / T ) ,
Δ T / T = ( Δ λ / λ ) ( 5 λ T / C 2 - 1 ) + ( Δ J / J ) ( λ T / C 2 ) .
Δ J / J = Δ K / K + Δ F / F - Δ D / D .
G = τ G ,
J ¯ = [ F / ( B 0 - B F ) ] ( τ b ¯ ) .
exp ( - K / T F ) = τ E L · exp ( - K / T L ) · F / ( B 0 - B F ) = K c F / ( B 0 - B F ) ,