FLOW VISUALIZATION AND INSTANTANEOUS VELOCITY-MEASUREMENTS OF SPRAY DRYER GAS AND SPRAY FLOWS USING PARTICLE IMAGE VELOCIMETRY

The technique of particle image velocimetry has been used to produce g ood quality instantaneous velocity maps of the gas and spray phases wi thin a pilot plant co-current spray dryer. Good quality now visualisat ion data provided by the use of the laser sheet as an intense source o f illumination has indicated that the air and spray flows were charact erised by an offset central jet with down flowing (right hand side) an d up flowing (left hand side) wall streams. This is significantly diff erent from what would normally be expected and it was suggested that t his was possibly due to a maldistribution of the air phase on inlet to the dryer.