Experimental Study of Air-Assist Atomizers for Fogging Systems

It is known that the temperature of the ambient air significantly affects the power output of gas turbines. To decrease inlet air temperature water injection at the intake of the turbine is commonly used. Existing air-assist atomizers consume significant more energy in the form of high-pressure air (about 6 bars) as compared to the jet impinging ones. Two new designs of the air-assist atomizers for fogger system are developed and studied. These atomizers differ from the existing ones by special air vortex chamber. It enables to achieve high tangential air velocities and reduce air input pressure. It is shown that at air pressure drop of 0.75–1 bar, the Sauter Mean Diameter of droplets is in the range from 20 to 25 μm when air-to-liquid flow rate ratio is equal to 4:1. Water supply pressure was in the range of 0.5–1 bar during the tests and its value did not markedly affected droplets diameter. It is expected that during optimization of the design and operating condition (air and liquid pressure), the size of the droplets would be further reduced. When air pressure was above 1 bar the droplets diameter was almost not affected by this parameter. Droplet velocity and droplet flux distribution along spray radius were also measured. It was found that the droplets distribution along radius is almost uniform. Spray cone was 30° for one device and 90° for the other.