Study On The Influence Of The Structural Parameters Of The Pneumatic Atomizer On The Atomization Performance

The core structure of the pneumatic atomizing nozzle belongs to the single oil-way centrifugal nozzle,and the structural parameters have a direct influence on the fuel atomizing characteristics.This article takes a certain pneumatic atomizing nozzle as the research object,and uses experimental methods and numerical simulation methods to study the influence of the structural parameters of the pneumatic atomizing nozzle on the atomization characteristics.In order to ensure the correctness of the numerical simulation,an experimental study of the atomization characteristics was carried out.The parameters of the flow characteristics of the pneumatic atomizing nozzle under various operating conditions,the atomizing cone angle,the Sautel mean diameter(SMD),and the non-uniformity of the circumferential distribution were measured,and the laws of each parameter under different operating conditions were obtained.The experimental nozzle structure was used as the reference structure parameter,and a 1: 1 model was established using UG software,which mainly includes the gas phase channel,liquid phase channel and external flow field of the pneumatic atomizing nozzle.By studying the calculation method,the calculation method of the VOF implicit solution is adopted.The comparison with experimental results confirms the referability of numerical calculation results.In order to analyze the underlying cause of the influence of the structural parameters on the atomization characteristics,the flow process inside the nozzle and the opening process of the atomization cone angle were analyzed.The inlet parameters and model parameters were changed to obtain the inlet pressure parameters,the tilt angle of the swirl vane,the nozzle diameter,and the angle of the near-flare bell mouth.Changes to the atomization cone angle,flow coefficient,nozzle internal tangential speed,nozzle axial direction,tangential The relationship between parameters such as direction velocity and liquid film thickness near the nozzle.The experimental results show that with the experimental nozzle of the standard structure,the flow coefficient decreases with the increase of the fuel supply pressure,and then remains unchanged.When the fuel supply pressure is small,the atomizing cone angle is larger,and becomes smaller as the fuel supply pressure increases.By increasing the air supply pressure,the atomization quality can be significantly improved,but increasing the oil supply pressure while maintaining the same air pressure makes the atomization quality worse.The atomization particle size at different positions from the nozzle has the same trend with the oil supply pressure,but the atomization particle size that is closer to the nozzle is larger.Through numerical simulation,the process of filling the swirl chamber after the fuel flow out of the oblique hole piece is clearly captured.The cross-section air core shape of the swirlchamber undergoes a comma-petal-circular change process.Finally,the diameter of the air core decreases and stabilizes.It takes time to open the spray cone angle.In the process of opening the atomization cone angle,it goes through four stages of mist cone-liquid-incomplete cone angle and full expansion.At the same pressure difference,with the increase of the inclination angle of the swirl plate,the atomizing cone angle and the tangential velocity in the swirl chamber are increased,and the flow coefficient and the liquid film thickness are reduced.The increase of the nozzle diameter increases the air core diameter,liquid film thickness and atomizing cone angle,and reduces the flow coefficient.The increase of the bell mouth angle at the exit has little effect on the upstream parameters such as the internal flow field and flow coefficient,which reduces the thickness of the liquid film,so that the atomizing cone angle increases first and then decreases,and there is an optimal bell mouth angle.