Velocity measurement techniques in liquid sprays using laser Doppler velocimetry

In many applications, there exists a velocity lag between droplets and a surrounding gas. The measurement of gas velocity must therefore be performed separately from the measurement of droplet velocity. This is the objective of a technique implemented in order to measure gas velocity, in the presence of droplets. A laser velocimeter adjusted for reference beam mode was used in a water spray. Satisfactory results are obtained and it is shown that, providing the gas flow is correctly seeded with small particles, a velocity measurement of gas velocity is yielded even with a large number of droplets.