An experimental investigation on the radiation characteristics of plasma jet in the plasma-propellant interaction

Summary form only given. During the electrothermal chemical (ETC) ignition, radiation heat transfer plays an important role, which calls for a comprehensive understanding of the radiation characteristics of the plasma jet. Therefore in this work, an experimental investigation was conducted on the radiation characteristics. Three types of propellants with different emissivity were ignited by two different schemes, namely, the radial discharge scheme and the axial discharge scheme, under the charging voltages of 5 kV, 7 kV and 9 k V. A capillary discharge setup and a gap discharge setup were utilized in the experiments to represent the axial and radial discharge ignition schemes respectively. Additionally, a fused-silica window of 3 mm in thickness was used to ensure that the propellants were interacted by plasma jet only through radiation heat transfer. Various diagnostic devices were used. The spectroscope and intensified charge-coupled device (ICCD) were used to measure the surface temperature of the propellants while CCD was used to visualize the plasma jet. Moreover, the propellant surface conditions were investigated by a scanning electron microscope. Results show that the percentage of radiation heat transfer absorbed by propellants is proportional to the emissivity. And the results are supposed to help in verifying the numerical model of plasma-propellant interactions.