Mass-spectrometric analysis of hypersonic flows

Abstract

Quantitative mass-spectrometric measurements have been made of the relative species concentrations in non-equilibrium hypersonic flows produced in a shock tunnel. Some partially dissociated flows of either nitrogen, air, or carbon dioxide have been analysed at nominal stagnation enthalpies up to 60 MJ kg-1. Emphasis was placed on eliminating two basic problems which had not been resolved by previous workers. One involved the dependence of electron-impact ionization cross-sections of neutral molecules on their vibrational temperature. The other was to perform a calibration which fully accounted for the effects of separation of the neutral species in the molecular beam sampled from the flow. Experimental results are compared with approximate calculations.