UTILISATION OF LASER DOPPLER AND LASER TRANSIT VELOCIMETERS IN SUPERHEATED, SATURATED AND WET STEAM FLOWS.

A laser doppler (LDA) and two types of laser transit velocimeters (LTV) have been used in steam. The facility comprises a two-dimensional tunnel and a small instructional turbine. For the LTV's only the back scatter alignment is applied, while both forward and back scatter configurations are examined for the LDA. In contrast to the LTV, the laser doppler system requires seeding. A pneumatic atomizer produces water droplets upstream of the measuring station. A computer program accounts for droplet evaporation. This allows the ideal initial droplet diameter to be calculated.