Experimental Study On Spray Steadiness Of Internal-mixing Twin-fluid Atomizer

Using the interaction between gas and liquid,the internal mixing air atomizing nozzle can better improve the atomization effect,so it is widely used in various power devices.Studying the spray steadiness of the internal mixing air atomizing nozzle helps to reduce combustion noise and improve combustion instability.In this paper,the experimental research method is used to study the changes of the experimental images of spray images and spray characteristics by using water and air as the medium.The results show that:(1)The spray fragmentation image and the spray standard deviation image at the near nozzle can reflect that the spray becomes unstable first as the gas-liquid mass flow ratio increases.When the GLR continues to increase to a larger value,the atomization tends to be stable.(2)As the axial distance of the nozzle increases,the standard deviation of the average diameter and the characteristic diameter of the spray is reduced,and the spray becomes stable;at the axial distance of 15 cm,from the center of the fog field to both sides,Souter The standard deviation of the average diameter and the characteristic diameter is reduced,and both sides of the fog field are more stable than the middle.(3)In the axial position of different nozzles,with the increase of gas-liquid mass flow ratio,the stability of droplets with different particle sizes is different,and when the gas-liquid mass flow is relatively large,due to the promotion of gas relative to liquid fragmentation,different The fast Fourier transform of the droplet size of the size and particle size shows an amplitude peak near a specific frequency,and the fluctuation of the same frequency is the main cause of the instability of the spray.(4)The nozzle structure also has an effect on the stability of the internal mixing air atomization spray: as the nozzle inlet fillet and the roughness of the inner wall of the nozzle increase,the gas-liquid two-phase interaction increases,the spray becomes unstable;the size of the nozzle diameter affects The gas-liquid two-phase mixing and the atomization after the liquid exits the nozzle,as the diameter of the nozzle increases,the secondary atomization of the liquid extends toward the lower axis,and the spray becomes more and more unstable at 15 cm in the axial direction of the nozzle.