掺混燃油在离心喷嘴内的流动与雾化特性研究

燃料性质的改变会导致雾化特性的变化，针对乙醇掺混航空煤油在离心式压力雾化喷嘴内的流动与雾化特性开展了研究。通过耦合流体体积法(VOF)和离散相模型(DPM),研究了不同乙醇掺混体积分数下掺混燃油在离心式喷嘴中的内部流动和外部雾化过程。研究结果表明：在压差不变时，喷嘴内空气芯直径随着掺混燃油内乙醇体积分数的增加而增大；而液膜厚度则与空气芯直径成反比，随着乙醇体积分数的增加而减小。喷嘴出口的速度随着乙醇体积分数的增加而增大；在油膜表面的波动及气动力的共同作用下，油膜失稳形成液滴，获得了不同比例下掺混燃油在喷雾外流场内的喷雾粒径分布特征，随着掺混乙醇体积分数的增加，液滴的平均直径逐渐减小。

Flow and Atomization Characteristics of Blended Fuel in a Centrifugal Nozzle

Changes in fuel properties will lead to changes of atomization characteristics.The flow and atomization characteristics of ethanol mixed with aviation kerosene in centrifugal pressure atomization nozzles were studied.Through the coupled volume of fluid (VOF) and discrete phase model (DPM),the internal flow and external atomization processes of blended fuel in a centrifugal nozzle under different ethanol blending volume fractions were studied.The research results show that when the pressure difference is constant,the diameter of the air core in the nozzle increases with the increase of the ethanol volume fraction in the blended fuel,while the thickness of the liquid film is inversely proportional to the diameter of the air core,and it decreases with the increase of the ethanol volume fraction.The velocity of the nozzle outlet increases with the increase of ethanol volume fraction; the droplets are formed due to oil film instability under the influence of the fluctuation of the oil film surface and the aerodynamic force; the distribution characteristic of droplet diameter of fuel with different blending ratios in the outer atomization flow field is obtained.As the volume fraction of blended ethanol increases,the average diameter of droplets gradually decreases.