Atomization-a new type for better gas scrubbing

Atomization of water by air in a Venturi scrubber was studied by stop-action still photography (0.5 μs) to determine how and where atomization takes place and what happens to the droplets formed. It was shown that two distinct types of atomization can be made to occur: "cloud-type" and "drop-type". Cloud-type, a unique type of atomization, occurs when water is injected as a stream from nozzles greater than approximately 1 mm i.d.; drop-type occurs when smaller nozzles, spray nozzles, or dropping tubes are used which causes the water to enter the atomizer in drop (or sheet) manner. Atomization of streams produces smaller than predicted (< 30 μ dia.) droplets which group in cloud like form. Atomization of drops gives the predicted "larger" size droplets for which size range and distribution equations have been developed and verified in many previous investigations. Both of these types of atomization were produced in the same apparatus of this study simply by modifying the water inlet nozzle diameters. The difference between the two types of atomization is explained on the basis of surface tension considerations: There is less surface area in a stream of water than in the same volume of water as drops, so less work is required to break up a stream.