Flow imaging for multi-component flow measurement

Abstract

Multi-component flow measurement is of increasing importance for resource exploitation, energy conservation, and biochemical process applications. Conventional flowmeters which endeavour to average a property of the flow over the pipe cross-section are unsuitable for accurate measurement in the many cases where the component distribution is spatially and time varying in a statistically non-stationary manner. Flow imaging which, like medical tomographic imaging, gives a cross-sectional image of the component distribution leads to the possibility of a much more accurate measurement. The paper describes the basic theory of flow imaging and the system arrangement necessary for its implementation. We also describe a specific arrangement using pulsed ultrasound echo transducers and an acoustic backprojection algorithm for image reconstruction. This shows that a 12-transducer view system can resolve a long single 6-mm diameter void parallel to the axis in a physical model corresponding to a liquid/gas flow in a 78-mm diameter pipe.