HIGH TEMPERATURE SECONDARY REFERENCE POINTS BASED ON MELTING POINT OF REFRACTORY OXIDES HEATED BY CONCENTRATED SOLAR ENERGY

摘要

The expansion of industrial processes to ever higher temperatures has created the related need for precise measurements of physical phenomena in previously unexplored temperature regimes above 2000°C. Secondary temperature reference points have been established above 2000°C (ITS 90) based on the melting of several refractory oxides. We present one approach, to realize the melting of the product and to measure its freezing. We use a 2 kW solar concentrator to supply a radiant energy rotating reactor filled with the various refractory oxides. This set up allows to: (1) reach the high temperatures necessary to melt the refractory oxides, (2) perform high quality temperature measurements because the melted cavity approaches a black-body, (3) preserve the purity of the material, (4) realize optical temperature measurements at 1.6μm and 8-10μm. Four refractory oxides were used for the experiments: HfO_(2), Y_(2)O_(3), Al_(2)O_(3), Ho_(2)O_(3).