Measurement of the radiation intensity beyond the front of strong shock waves for a methane-nitrogen gas mixture

摘要

Measurement of the radiation intensity beyond the front of strong shock waves for a methane-nitrogen gas mixture was investigated. A shock tube composed of three parts, high-pressure chamber (HPC), the low-pressure chamber (LPC), and the expansion volume, was chosen for the experiment. The chambers were separated by a 50-μm brass membrane, whereas the LPC was separated from the expansion volume by the output aluminum diaphragm. The HPC was filled with a stoichiometric hydrogen-oxygen mixture up to a pressure of 3 atm. Then, with the use of helium and argon, summary pressure was elevated up to 10 atm. The radiation that passed through the slit of the spectrometer and decomposed in the spectrum was then focused onto the photocathode of a LaVision Picostar HR12 high-speed ICCD camera that provided signal amplification by a factor of 10 ~6. It was found that the basic contribution to the radiation emitted beyond the shock-wave front in the methane-nitrogen mixture is introduced by both the violet CN system and C _2 Swan bands.