In this study,spectroscopic measurements of CO2- Ar arc plasma flow are conducted using a hollow electrode arc heated wind tunnel. In CO2- Ar plasma,radiation of C2 Swan band system is predominant. Other molecular and...In this study,spectroscopic measurements of CO2- Ar arc plasma flow are conducted using a hollow electrode arc heated wind tunnel. In CO2- Ar plasma,radiation of C2 Swan band system is predominant. Other molecular and atomic spectra are not observed except Cu spectra which are produced due to the electrode melting. Background continuum radiation is observed and overlapped with C2 Swan band system. Temperature evaluation of CO2- Ar arc plasma flow is conducted by the area intensity method and temperature distribution is obtained along the stagnation streamline around a disk model. It is found that the vibrational temperature is much higher than the rotational temperature in the free stream region due to the vibrational nonequilibrium process. In the shock layer,the rotational temperature increases by about 1 000 K while the vibrational temperature decreases by about 1 000 K. Energy exchange between translation and vibration modes is activated in the shock layer,resulting in the decrease of the vibrational temperature. However,the vibrational temperature is still higher than the rotational temperature,indicating that the vibrational relaxation process is not completed. In conclusion,the thermochemical state of the CO2- Ar arc plasma flow is in the vibrational nonequilibrium state along the stagnation streamline around the disk model.展开更多
文摘In this study,spectroscopic measurements of CO2- Ar arc plasma flow are conducted using a hollow electrode arc heated wind tunnel. In CO2- Ar plasma,radiation of C2 Swan band system is predominant. Other molecular and atomic spectra are not observed except Cu spectra which are produced due to the electrode melting. Background continuum radiation is observed and overlapped with C2 Swan band system. Temperature evaluation of CO2- Ar arc plasma flow is conducted by the area intensity method and temperature distribution is obtained along the stagnation streamline around a disk model. It is found that the vibrational temperature is much higher than the rotational temperature in the free stream region due to the vibrational nonequilibrium process. In the shock layer,the rotational temperature increases by about 1 000 K while the vibrational temperature decreases by about 1 000 K. Energy exchange between translation and vibration modes is activated in the shock layer,resulting in the decrease of the vibrational temperature. However,the vibrational temperature is still higher than the rotational temperature,indicating that the vibrational relaxation process is not completed. In conclusion,the thermochemical state of the CO2- Ar arc plasma flow is in the vibrational nonequilibrium state along the stagnation streamline around the disk model.
