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.
A novel high flow rate gas-assist atomizer for liquid atomization was developed. The method of liquid supply in the zone of maximal air velocity is used. It is shown that it is possible to achieve fine atomization as the relative velocity between gas and liquid is very high. However actual sprays have droplets with larger size due to the rapid decrease of the difference between air and liquid velocities. So droplets disintegrate mainly due to the turbulent velocity fluctuations of the air flow. The experimental study included two stages: laboratory tests and field tests inside a full size boiler of a 220 MW power station. At the first stage, several atomizer modifications were tested using water and compressed air. Droplet size was measured by a special Laser Light Scattering method. Liquid flow rate was equal to 3500 kg/hr. The liquid atomization quality at each cross-section of the spray was estimated by measuring the liquid-droplets sizes at several stations across the spray. The tests were carried out for two distances, 30 and 40 cm, downstream of the nozzle. The tests show that for the proposed atomizer droplets SMD was reduced from 135 to 67 microns. Droplets SMD maintains constant value when liquid flow rate is reduced by 50%. The spray angle was kept as in a standard atomizer and equal to 110 degrees under all operating conditions. It was found that to obtain this angle, the pressure downstream of the nozzle core should be atmospheric. The atomizer with the best performances was selected for the field tests. It was assumed that the atomizer which shows the best results for air-water mixture would be superior also for steam-fuel mixture. Field tests of the atomizer within the burner of an actual power station in Israel (boiler by Babcock Borsig Company), demonstrated a significant reduction in NOx content, from 540 to 270 ppmv as well as better service conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.