A device was perfected at the University of Wisconsin in 1944 for measuring the instantaneous combustion temperatures in the diesel engine throughout the combustion cycle (6). This device is known as the electro-optical pyrometer, and as the name implies, it measures temperature by electronic means.
The Mechanical Engineering Department of the University of Wisconsin considered that this device with certain changes and developments might very well adopt itself to the measurement of blade temperature in a gas turbine since the blades get hot enough to emit radiation in the red and infra-red range of the spectrum. The electro-optical pyrometer would be ideal in this application because it would follow instantaneously the temperature variation along the blades as they rotated at high speeds. The desired pyrometer would require high frequency response because of the turbine speed, and also high gain since the radiation intensity would be low compared to that of diesel combustion. For frequency response required see Appendix 2.
The Allis-Chalmers Company of Milwaukee became interested in this ideas, and donated to the University a turbo supercharger which they had been operating as a gas turbine.
The work was divided into two phases, that of constructing the test stand for turbine operation, and secondly the design and construction of the electro-optical pyrometer required to make the temperature determinations. The writers concentrated on the second phase, i.e., the electronic apparatus, so consequently this thesis will be concerned primarily with the radiation theory and the electronic development. A more rigorous treatment of the turbine test stand will be found in another thesis. (4).
Copyright 1947
Engine Research Center
University of Wisconsin-Madison