Temperature Measurements of Plasma Jet Using Emission Spectroscopy

An inclination towards electrically driven plasma burners is expanding due to their ability to replace fossil fuel-based burners and reduce carbon dioxide emissions. However, presently only burners with thermal power up to ~6MW are available. For large-scale industrial applications, scaling-up of existing burners is required. To achieve this, it is primarily important to understand the development of plasma jets at different operational conditions of the burner. This work aims at measuring the temperature of the plasma jet in a laboratory-scale burner, for the understanding of the impact of different plasma gases for varying inlet properties such as velocity and power. A primary target is also to compare and analyze the agreement between experiments and data from numerical modeling. Considering the high temperature of the plasma jets (7000 K), optical emission spectroscopy is selected as a diagnostic tool. The excitation temperature is determined using the two-line method considering Copper line intensities near 515nm and by comparing the measured emission spectra with those calculated using the Specair software. It was found that the plasma gas with high-density shows lower temperature, and the temperature of the jet increases with the increase in power input. It can also be concluded that the error percentage between experimental and computational results is less than 10%.