离心喷嘴内部流动与雾化特性数值模拟

Numerical Simulation of Internal Flow and Atomization Characteristics of Centrifugal Nozzle

中文关键词:  离心喷嘴  燃油雾化  空气涡  柱状破碎  瑞利-泰勒不稳定性  航空发动机

英文关键词:centrifugal nozzle  fuel atomization  air vortex  columnar fragmentation  R-T instability  aeroengine

中文摘要:

      为探究不同供油压力对离心喷嘴燃油雾化场的影响，结合燃油喷嘴雾化试验研究结果与燃油雾化气液两相流数值模拟 分析，研究了不同工况下离心喷嘴的雾化特性。结果表明：随着燃油压力的提高，液体的动量比增大，雾化锥角在低供油压力时受 供油压力影响，后受喷嘴结构影响，整体趋势为先增大后减小。液体在填充过程中，在喷嘴中心气相与液相交界处形成1个中心 负压区，大量空气挤入该区，致使在喷嘴内部形成1个尾部呈锥形的空气涡。在旋流室上腔与雾化锥角下游区内侧，由于空气与 液体剪切力的作用，出现多个小型涡结构，这些涡的结构与供油压力大小有关。当供油压力为0.4 MPa时，韦伯数较低，在液膜表 面产生一种沿液膜表面以正弦方式变化的表面波；当供油压力为2.7 MPa时，韦伯数较高，液体柱状破碎由瑞利-泰勒（R-T）不稳 定性主导。

英文摘要:

      In order to investigate the effect of different fuel supply pressures on the fuel atomization field of centrifugal nozzles, the atomization characteristics of a centrifugal nozzle under different working conditions were studied by combining the results of fuel nozzle atomization experiments and numerical simulations of fuel atomization gas-liquid two-phase flow. The results show that the liquid momentum ratio increases with the increase in fuel pressure. The spray cone angle is influenced by the supply pressure at low supply pres? sure, and then by the nozzle structure, with the overall trend of first increasing and then decreasing. During the liquid filling process, a central negative pressure zone is formed at the interface of the gas phase and liquid phase in the nozzle center, a large amount of air is squeezed into the zone, resulting in the formation of an air vortex with conical tail inside the nozzle. In the upper chamber of the swirl chamber and the inner side of the downstream region of the spray cone, multiple small vortex structures appear due to the shear force of air and liquid, these vortex structures are related to fuel supply pressure. When the supply pressure is 0.4 MPa, the Weber number is low, and on the liquid film surface, a surface wave is generated that varies sinusoidally along the liquid film surface. When the supply pressure is 2.7 MPa, the Weber number is high and the liquid columnar fragmentation is dominated by Rayleigh-Taylor (R-T) instability.