Simultaneous measurement of velocities and particle sizes for injection systems and ramjet combustors

Measurements that simultaneously allow determination of velocities and particle sizes in two-phase flows are of great interest in fuel injection systems used in jet propulsion and liquid rockets, as well as in other fields, such as fluidized beds, pulverized fuel combustion and filtration processes. A novel technique based on the use of a modified Laser Doppler Anemometry (LDA) which permits instantaneous measurement of the sizes and velocities of individual particles in the 20-800 micron size range with velocities up to around 600 m/s was developed. Its principle lies on the relation between the drop diameter and the pedestal amplitude, a characteristic of its LDA signal. The paper describes the technique developed in order to obtain the parameters of that relation.