Research On Structure And Atomization Characteristics To Swirl Atomizer

Swirl atomizer is a common structure to atomizing nozzle.Built-in spiral device is an effective swirling structure.Compared to other types of atomizers,because of simple structure and good low-pressure,it is widely used in fire protecting,environment and chemical engineering and so on.According to swirl atomizer and the advanced nozzle comprehensive test bed and CFD numerical simulation technology,This article has carried on the numerical simulation and experimental research around the core structure of the nozzle and the flow field characteristics.Analyzing the structure characteristics of the screw core nozzle and spray requirements, First, Fluid motion analysis method and motion equation was introduced,and Swirl atomizer internal and external flow field motion state was analyzed emphatically.It was obtained that the structure of the flow field consists of velocity,pressure distribution inside the nozzle characteristic and the nozzle external cloud droplets motion equation,the flow field characteristics and swirl atomizing mechanism was analyzed in theory.The method of CFD simulation has been discussed for Swirl atomizer. Under the same condition of import speed and export pressure,The model of atomizer was simplified.It includes that clapboard length is equal to the atomizer diameter and the bottom of the screw core is fixed on the straight pipe.3D model was divided with hexahedral grid structure, choosing turbulence model,and the numerical simulation was carried on continuum- water.According to equal coupling,Swirl atomizer and core spiral Angle, Angle spiral or other core structure parameters changing, the flow field velocity and pressure distribution was analyzed on numerical simulation. Compared with ordinary straight nozzle,it shows that swirl atomizer exit velocity is bigger,the velocity distribution is more homogeneous and atomization effect is better,jet distance is more far.For the swirl atomizer,outlet axial velocity decay quickly,others,it has the obvious tangential velocity and bigger spray angle.Owing to the effect from the refluxing fluid and air entrainment phenomenon,it will form a air cone at the exit location.Jet flow will be squirted so that swirl atomizer shows the atomization characteristics.When the nozzle cone angle is about 90°, the fluid pressure loss minimum and reflux relatively small,relatively uniform velocity distribution,others,the axial velocity and tangential velocity is relatively large and most optimization.Rotary core helix angle is about 15°,the flow field inside the nozzle axial velocity and tangential velocity is relatively large,low pressure,most optimize.In experimental research,the contrast experiment was set up about straightway atomizer and swirl atomizer.The flow characteristic and distribution of spray experiments has been completed.It was obtained that the flow curve consists of flow rate- pressure drop curve,the atomization Angle- pressure drop curve and spray distribution curve.The experimental data has well verified the results of theoretical analysis and numerical simulation.