A novel pyrometric technique is being developed in Electricite de France (EDF) for measuring the surface temperature of the moving blades of partial load steam turbines. This technique uses the photothermal effect to slightly (temporarily) modify the superficial temperature of the object. Theoretical considerations show that the measurement is proportionnal to successive derivatives of Planck's function. The point is that the measurement is thus made. insensitive to background radiation partially reflected to the detection system by the object itself. Moreover, the short duration of the operation (several microseconds) allows quick moving targets to be measured. We here use the method for monitoring the temperature of the moving blades of partial load steam turbines in EDF nuclear power plants. A rod-shaped probe using fiber optics is being built to take measurements in real conditions. Some laboratory preliminary results show effectiveness and good accuracy of the method. Further studies will permit the extension of this new method to many industrial problems where non-contact temperature measurements in adverse radiative conditions are required.

Date Published: 1 March 1990
PDF: 12 pages
Proc. SPIE 1313, Thermosense XII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications, (1 March 1990); doi: 10.1117/12.21943

Published in SPIE Proceedings Vol. 1313:
Thermosense XII: An International Conference on Thermal Sensing and Imaging Diagnostic Applications
Sharon A. Semanovich, Editor(s)