An optical study of ignition in gases

• Main Author: Wilson, John William Ronald
• Published: Imperial College London 1967
• Subjects: 543
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.622991

The ignition of flowing gases by a hot surface is considered briefly in relation to the potentially hazardous environments associated with supersonic aircraft. A theoretical model is proposed as a basis for investigating pre—ignition conditions in the neighbourhood of a heated surface exposed to a combustible gas stream. By assuming a series of quasi—steady states prior to ignition onset, critical heat release rates are determined, which, it is suggested, may be used to establish safe conditions for any system in which the distributions of temperature and velocity are specified. The development of suitable experimental systems is described, along with the application of various optical methods to the study of conditions preceding ignition in the systems concerned. Interferometry is found to be ideally suited for this purpose, under the experimental conditions considered, and a detailed account is given of the relevant optics and analysis involved. A discussion of the results obtained from a thermal analysis for an ethylene—air mixture includes the deduction of potentially useful kinetic data. It is concluded that the method described in this research could be profitably extended and suggestions are given for developing the present work further.