A5.1 - Flow Sensors - Recent and Future Developments

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
A5 - Flow Sensors II
S. Becker - Universität Erlangen-Nürnberg (Germany)
112 - 117


The objective of the presentation is to provide a comprehensive overview of recent developments concerning sensors that can be used to measure the flow velocity. Velocity measurements can be understood to represent spatially integrated and pointwise values.

The current overview will be focussed on pointwise Measurements techniques including sensor developments in the filed of thermal anemometers, pressure-based velocity sensors and laser measurement techniques.

All laser based velocity measurements are particle based techniques, e.g. laser Doppler anemometry (LDA), particle image velocimetry (PIV), Doppler global velocimetry (DGV) and laser transit velocimetry (LTV). These velocity sensors rely on the precense of tracer or seeding particles in the flow that not only follow all velocity fluctuations but are also sufficient in number providing the desired spatial and temporal resolution of the flow field. Suitable particles is still an open problem, because it is desirable that these tracer are at the same time good light-scattering centers, since this improves the signal quality for a given incident laser power. The fact that flow tracking demands small particle diameters while light scattering improves with increasing particles size already suggests the requirement for optimization when selecting seeding particles. The best way would be to avoid an addional particle seeding by only using the natural particle distribution in the flow. The
presentation shows some recent developments concerning laser based flow sensor which allow measurements without any additional particle seeding in air flows.

In the next major issue the presentation will give an overview of current activities in measurement techniques capturing the velocity measurements in distribution in a point, line, plane or volume. The accuracy of the measurements, spatial and temporal resolution, measurement time and the complexity will be discussed.

In the end it future developments and challenges for flow sensors for scientific but also for industrial applications will be shown.