In this work gaseous fuels were released continuously and concentrically into confined annular co-flows of turbulent hot air. Following injection the fuel and air mixed and at some length downstream of the nozzle the reactive mixture autoignited. Original phenomena are reported of autoignition spots, unsteady flame propagation and extinction or flashback.
The frequency of the spots was measured, as were their acoustic and chemiluminescence characteristics. Optical measurements of the autoignition locations were made and used to estimate mean delay times from injection. As would be expected...