Masters Theses

Date of Award

8-1995

Degree Type

Thesis

Degree Name

Master of Science

Major

Physics

Major Professor

Arthur A. Mason

Committee Members

Horace Crater, Christian Parigger

Abstract

Equilibrium or near-equilibrium absolute temperatures are measured by the use of the line reversal method, which involves the comparison of broad-band, continuum radiation with narrow molecular or atomic signatures of selected seed species. The temperature is obtained by the adjustment of the continuum radiation intensity to or near the reversal of seed absorption and seed emission. The technique of sodium line reversal is addressed in a laboratory setting in support of application to the Arnold Engineering Development Center (AEDC) Impulse Facility. Development of the double beam method included initial, static measurements in a flat flame burner, and time resolved measurements in a laboratory shock tube. Final measurements in the Impulse Facility were not possible due to monetary constraints; however, necessary calculations and investigations were performed as if the tests were to occur. Arguments for performing these measurements are presented. General theory of the sodium line reversal technique is presented and referenced. It includes a discussion of the Planck's blackbody radiation distribution and its relationship to true temperature through the emissivity of a material that is not a blackbody. The atomic theory of the sodium D lines at 589.0nm and 589.6nm is briefly reviewed. Instrumentation for data collection is discussed in detail. This includes optical and electronic equipment. Where appropriate, photographs are included for clarification of optical arrangements. Problems occurring along the way are presented and dealt with, for example, temperature errors due to optical alignment, and methods of introducing salt into the different test environments. At each stage of development of the application for the burner and the shock tube, experimental results are compared to expected results. The expected results are generated by computer calculations and by thermocouple measurements of the flame. Good agreement is found for both the flame and the shock tube. Uncertainty calculations, such as calibration uncertainty and signal to noise ratios, accompany the results for both the flame and the shock tube.

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