Measurement of local frequency distributions of particle velocities in gas solid flows - Fundamental investigations for the use of a laser Doppler velocimeter

The use of a laser Doppler velocimeter (LDV) as a metering method for determining comprehensive frequency distributions, is reported. Problems caused by relatively large particles or wide particle size distributions are discussed with regard to a representative comprehension of all individual singles. A method for optimal matching of optical and electronic measurement systems to the assumed characteristics of dispersive flowing phases is given. In this manner the local frequency distributions of the axial particle velocities are determined for a vertical gas-solid flow through a pipe. It is found that by varying the flow parameters characteristic relationships could be determined.