Swirl Atomizer Design for Evaporative Cooling of High Temperature Compressed Air Stream

Faculty of Mechanical EngineeringGIK Institute of Engineering Sciences and Technology,PakistanThis work presents the design of a swirl atomizer which provides a certainflow rate of water with required spray quality for effective evaporative cooling ofhigh temperature compressed air of a turbocharged diesel engine. By using wetcompression theoretical model, the desired mass flow rate of water and qualityof spray for effective evaporation was determined. The evaporative cooling de-creases the intake air temperature of engine and increases its mass flow rate, withconstant fuel-to-air ratio this increase in air mass flow rate increases the powerof the engine. Abramovich’s theory along with Kliachko’s theory was followedto design a swirl atomizer that provides the required spray characteristics. In-formation has been presented on the effect of atomizer inlet port geometry, swirlchamber design, orifice design and the importance of swirling inside atomizer.The effects of atomizer geometric parameters such as angle of conical conver-gence, length-to-diameter ratio of inlet port and of swirl chamber were examined.It was concluded that the length-to-diameter ratio of swirl chamber has a signif-icant effect on atomizer flow rate and spray cone angle determination. With thesame injection pressure, its increase leads to enhancing the mass flow rate whiledecreasing the spray cone angle from the atomizer. The atomizer was tested ex-perimentally and through fluid flow modeling for its required spray quality andthe results were fairly close with theoretically predicted results. The design ofatomizer was also optimized for required spray characteristics by modeling thefluid flow inside the atomizer.* * *