Cite as:
Heß R, Proyer S, Hahn P, Semerad E, 1999, "A new setup for the determination of emissivity by a dynamic method" High Temperatures - High Pressures 31(3) 307 – 320

A new setup for the determination of emissivity by a dynamic method

Rudolph Heß, Siegfried Proyer, Peter Hahn, Ernst Semerad

Received 09 September 1997, in revised form 11 November 1998

Abstract. An apparatus is described which enables the measurement of total emissivity with a dynamic technique at temperatures from 500 °C to 1800 °C and at incident angles from 0° (perpendicular to the sample surface) to 60°. The total emissivity is determined by a comparative method, where the radiation emitted from the surface of the sample is compared to the radiation emitted from a reference blackbody of defined emittance (ε approx 1). The cylindrical samples with a diameter of 15 mm and a thickness of 4 mm to 6 mm are heated by radiation at the bottom of an inductively heated cylindrical graphite cavity, which additionally serves as the reference. Subsequently the samples are lifted to the measurement position, where a thermopile detector and a photodiode sensor are applied to measure the emitted radiation. Specimen temperature is measured via sapphire light-pipe sensors and a blackbody hole in the specimen. The actual surface temperature of the samples is calculated by a one-dimensional time-dependent numerical approach. The measuring process and the data acquisition are fully automated.

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