Quantifying the effect of thermal heat radiation emitted by the walls of a climatic chamber on temperature measurements

¹ CETIAT, Domaine scientifique de la Doua, 25 avenue des Arts, 69100 Villeurbanne, France
² IUT Mesures Physiques, 28 Avenue Léon Jouhaux, 42100 Saint-Étienne, France

^* Corresponding author: jacques-olivier.favreau@cetiat.fr

Abstract

The study consists in quantifying the effect of the thermal radiation of the climatic chamber walls on air temperature measurements for contact thermometry. Air temperature measurements are affected by surface interactions with the environment, such as those of the thermometer and walls (surface condition, emissivity and air velocity). The walls of the enclosure are generally made of stainless steel, a potentially radiating material. To characterize the effect of the walls, we have varied environmental conditions such as the emissivity of the walls of the chamber and the sensors, the surface of the sensors, temperature and illumination. These different configurations allow us to deduce their impacts on the temperature measurements. To quantify this effect we simulated different configurations to isolate the radiation effect. Two surface states are tested: low emissivity metal surface and painted surface with matte black paint of high emissivity. This study highlights the effect of the walls on the air temperature measurements in the center of the climatic chamber. The experimental results were also subject to a theoretical verification using the equation of the standard ISO 7726 [1]. The quantification of the effect of radiation from the walls of the climate chamber on temperature measurements becomes significant from 100 °C. Quantification of thermal radiation is 0.4 °C at 100 °C and 0.8 °C at 150 °C.