Monitoring liq. and gas speed and throughput - using laser Doppler anemometer involving single and multiple wave conductors

摘要

The arrangement monitors the flow of two phase liquids and gases as well as aerosols using laser-Doppler anemometry. It involves evaluating electronically the information contained in the light dispersed from two coherent beams intersecting at the measurement point. They enable speed of flow to be monitored even in narrow tubing without disturbing fittings at over pressure of approximately zero bars. This is achieved by pushing the laser light through a single wave conductor before dividing the beam and coupling the dispersed light into a multiple wave conductor before passing it to the optical receiver. The electronic evaluation involves separating at least two frequency ranges, normalising them for intensity and integrating them w.r.t. time.