Experimental Study On The Influence Of Internal Flow On Atomization Effects Of An Internal-mixing Air-assisted Atomizer

The interaction between gas and liquid inside the internal-mixing air-assisted atomizer makes liquid jet break into small droplets,achieves better atomization effects.Thus,it is widely used in various kinds of power devices.And it is important to investigate the atomizing process of the internal-mixing air-assisted atomizer.In this paper,the experiment method is adopted to study the atomizer internal flow’s influence on atomization effect by adjusting the gas and liquid pressure and changing the GLR.In the experiment,water and air were used as atomizing media.The results are showed as follows:(1)The internal flow test system of the atomizer was built,and the flow characteristics of the atomizer,the internal flow in the mixed chamber and the sheet thickness inside the atomizer were studied.It showed that the gas in the mixing chamber of the atomizer increased and the sheet thickness became thinner when the GLR and air pressure increased,and that the fluid in the mixing chamber of the nozzle increased and the sheet thickness became thicker when liquid pressure increased.(2)The sheet breakup’s experiment system was built,and the breakup process were studied.It is believed that the sheet’s breakup process became easier and the liquid fracture occured at the atomizer exit when GLR and air pressures increased,besides,finer droplets was achieved and the effect of atomization got better.The situation is the opposite when increasing the liquid pressure.(3)The spray characteristic test system was built,and the study found that with the increase of GLR and air pressure,the gas in the mixing chamber of the atomizer increased and the sheet thickness became thinner,which had certain influence on atomization performance.On the one hand,increasing GLR and air pressures made the spray cone angle increased first and then got small.On the other hand,it let the Sauter mean diameter(SMD)and the D0.1 decrease,which means that the atomization effect was better.With the increase of GLR,the sheet thickness became thinner,it let the number of droplets in the particle size of 5um and the volume of small droplets increase.When liquid pressure increased,the sheet thickness became thick and broke into larger droplets,and the SMD and the D0.1 became bigger,which means poor atomization was achieved.The spray cone Angle showed the trend of increasing first and then decreasing.(4)Studies showed that the atomizer orifice diameter had significant influence on atomization.At low value of GLR,the sheet thickness of the atomizer whose diameter is 1.3mm was larger than the atomizer of 1.6mm.The liquid film was not prone to fragmentation,which increased the SMD and characteristic diameter D0.1,and the atomization quality became worse.However,when GLR increased,the sheet thickness of the atomizer of 1.3mm became smaller than that of the atomizer of 1.6mm,thin liquid film was easy to break and the SMD and the characteristic diameter D0.1 decreased,and atomization quality became better.