Systematic investigation of pipe flows and installation effects using laser Doppler anemometry—Part I. Profile measurements downstream of several pipe configurations and flow conditioners

The first part of this paper reports on an automated facility designed to investigate the influence of disturbed flows in pipes on the shift of the error curves of gas flowmeters in situ. This facility can be equipped with several pipe configurations (single and double bends, convergent and divergent sections, straight pipes up to 40 diameters in length etc.) as well as with various types of flow conditioners. It works with atmospheric air at flowrates of up to 5500 m³/h. A two-component semiconductor Laser Doppler Anemometer (LDA) is used to measure the spatial velocity and turbulence fields of the flow along the entire cross section in front of the flowmeter to be investigated. More than 150 velocity distributions have been determined for different pipe configurations at several flowrates and data have been collected to describe the corresponding flowmeter's behaviour. Some typical velocity profiles for the most usual pipe elements and flow conditioners are shown.

The second part of the publication, which will be presented in the following, compares the changes in the meter behaviour with the specific development of the flow characteristics downstream of the pipe configurations investigated. The model found to explain these metering effects will be described, evaluated and verified.