Abstract. We investigate the tracer gas pulse injection method for flowmetering of natural gas pipelines. The principle of the measurement consists of detecting the passage of the pulse at two locations along the pipeline, from which the time of passage is calculated. The measurement accuracy depends on how the pulse form evolves due to turbulent diffusion and convective distortion in the pipe, as well as due to the influence of bends. We discuss these factors to evaluate the applicability of the method to pipelines of kilometer distances. We also perform a three-dimensional numerical analysis to understand the spatial pulse dispersion, and numerical analysis shows that the influence of pipe bends was not significant. Both experimental and theoretical results indicate the existence of axial diffusion coefficients, even in pipelines with bends. These results enable us to predict the evolution of the pulse concentration profile. Finally, we demonstrate acceptable precision for practical flowmetering applications in actual utility pipelines.

Keywords: flowmeter, pipeline, natural gas, turbulent diffusion, tracer gas injection

Print publication: Issue 1 (January 2010)
Received 10 July 2009, in final form 17 September 2009
Published 16 November 2009