Cold Experiment Research On Internal-mixing Atomizer And Y-jet Nozzle

The nozzle atomization is widely used in almost all areas of industrial,transportation,agricultural,and our daily life.There are many types of nozzle,with oil burner mainly for burning oil being more widely used in industrial applications.The oil burners including:mechanical atomizer,air blast atomizer and combined atomizing nozzle.Y-jet nozzle and internal-mixing atomizer are two widely used air blast atomizers.The atomization of these two kinds of nozzle is the result of injected fuel acting with air(or steam),belonging to process of two-phase fluid atomization.Their variable load characteristics and atomization performances are more complicated,being the hot and difficult point on the research of nozzles.In this thesis,on the basis of summarizing the previous research,the design methods of two kinds of nozzles were analyzed.In order to determine the discharge characteristic and the flow characteristic curve,the spray test bench was set up.The best values ensure good spray case of discharge coefficient,cross-section ratio and mixing length were obtained.It pointed out the direction for the optimization design of nozzle.The research of cold experiment with water instead of oil,air instead of superheated steam was set up.The conclusions are as follows:Y-jet nozzle(1)With the fuel pressure 0.65Mpa,atomizing air pressure 0.5Mpa cases,the best cross-section ratio(F1+F2)/F3 of Y-type nozzle is 0.6:From the point of atomization effect,the greater the cross section ratio,the better the atomization effect,a larger value should be selected,it should be considered in practical application.;(2)Compared to the Y-jet nozzle with gases in the middle,the Y-jet nozzle with liquid in the middle has small flow rate error and good atomization effect.It should be used in the real application.Internal-mixing atomizer(1)With the fuel pressure 0.5Mpa,atomizing air pressure 0.6Mpa cases,mixing chamber pressure should be 0.7,orifice flow coefficient of internal-mixing atomizer should be about 0.88;(2)With the fuel pressure 0.5Mpa,atomizing air pressure 0.6Mpa cases,the best(F1+F2)/F3 to the atomization effect of internal-mixing atomizer is 0.5 and 0.625,the best range of F3/F1 is 2.57 and 2.18;(3)With the fuel pressure 0.5Mpa,atomizing air pressure 0.6Mpa cases,the best mixed length of internal-mixing nozzle is L3 =3 D3.