Some experimental techniques in the study of flame stabilization

The purpose of this note is to describe one or two techniques which are currently being used at Cranfield in various investigations into the effects of flameholder geometry and flow parameters on the process of flame stabilization. Much of the report is concerned with a description of the nitrogen dilution technique as a means of simulating low combustion pressures, and a comparison is made between this and the now established water injection technique. It is shown that many aspects of flame stability can be effectively studied by local injection of nitrogen directly into the combustion zone, with appreciable economies in the amounts of nitrogen required. A further application of this local injection method is also described which has proved useful in an investigation of the factors governing the amount of air entrained in the recirculation zone.