Jena 2013 – scientific programme

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P: Fachverband Plasmaphysik

P 20: Plasmatechnologie II

P 20.4: Talk

Thursday, February 28, 2013, 17:45–18:00, HS 5

2D-2λ-Pyrometry - a reliable method for electrode temperature measurement — •Alexander Alexejev, Thomas Barowski, Stephan Holtrup, Jürgen Mentel, and Peter Awakowicz — Ruhr Universität Bochum, Lehrstuhl für Allgemeine Elektrotechnik und Plasmatechnik

A reliable measurement of electrode temperatures within high intensity discharge lamps (HID-lamps) is becoming ever more imperative. Measurements on commercial HID-Lamps are difficult due to a non cylindrical shape of the electrode and a distorted view by the curvature of the tube. Especially the temperature at the electrode tip is hard to access with sufficient precision due to uncontrollable surface roughening. Surface roughening influences the emission properties of the electrode, thus making pyrometric measurements doubtful.

A reduction of such an influence can be achieved by measuring emission of a whole electrode surface at different wavelengths simultaneously. This can be done either by dividing the light beam and measuring each wavelength with a different camera, or by filtering the divided beams and focusing them back on a single camera. By forming a ratio from two measurements the effects of surface roughening on the temperature determination can be reduced significantly. Mathematically, the surface dependent emission coefficients ratio hardly contributes to the results.

The authors present the method of 2D-2λ-Pyrometry. The results from measurements on the Bochum model lamp will be presented to point out the advantages of the method.