Radiation Analysis Behind Hypersonic Shock Wave in Nitrogen Using a Spectroscope and High Speed ICCD Camera

Park’s two -temperature model for rotational and vibrational states of air in hypersonic flows of medium Mach numbers is known to give a deviation from the experimental data due to strong non-equilibrium conditions and non-Boltzmann distributions. The present study shows an establishment of hybrid measurement system of rotational and vibrational temperature by fitting the experimental data of N2 and N2 + behind strong shock waves using a free piston shock tube with the computational results of the SPRADIAN code. The spectra fitting between experiments and numerical results is good except for the spectrum region of contamination by hydrocarbons to ensure that this fitting method is feasible. The obtained rotational temperatures of N 2 and N2 + are quite different from that of Park’s model near the shock front and become the same level away from the shock front. On the other hand the vibrational temperatures of N2 and N2 + are lower than that from the shock front to all the way downstream.