The application of mass spectrometry to the study of mixing processes in confined and unconfined gas flows

This paper describes a novel flow tracing technique which has been developed to obtain data on mixing and dispersion processes in gaseous flow systems. Tracer gas is injected at low flow rates into an air stream. Choice of tracer gas-primary fluid combination in relation to gas properties and detection techniques is discussed. The mode of operation of the mass spectrometer is described together with the sampling system. Analysis of samples drawn from the flow field provides tracer gas concentration profiles throughout the flow and these may be used to yield information on mixing rates. Two examples are given which illustrate the use of the method.