An experimental study on the breakup of a conical liquid sheet from a pressure swirl atomizer was conducted by using a Particle Image Velocimetry (PIV) system. The variation of wavelength, wave speed and amplitude of ...An experimental study on the breakup of a conical liquid sheet from a pressure swirl atomizer was conducted by using a Particle Image Velocimetry (PIV) system. The variation of wavelength, wave speed and amplitude of wave versus liquid pressure was obtained. The results indicate that the cone half angle increases with liquid pressure. The stripped half wavelength liquid fragment seems to break into a series of drops immediately and no obvious contraction from liquid fragment to ligament is seen. The recorded images also show that both short and long wavelength waves exist simultaneously, and influence the breakup of the conical liquid sheet. The result of this study is useful for the purpose of developing and verifying the atomization model of spray produced by a pressure swirl atomizer.展开更多
为了研究气液同轴离心式喷嘴缩进室内部非定常流动过程,采用Level Set和VOF(Volume of fluid)相耦合的方法,结合网格自适应技术对缩进长度为8mm的液体中心式气液同轴离心式喷嘴流动过程进行了数值仿真研究,计算得到了较为精细的液膜一...为了研究气液同轴离心式喷嘴缩进室内部非定常流动过程,采用Level Set和VOF(Volume of fluid)相耦合的方法,结合网格自适应技术对缩进长度为8mm的液体中心式气液同轴离心式喷嘴流动过程进行了数值仿真研究,计算得到了较为精细的液膜一次破碎过程、流场结构和压力振荡特性。结果表明:液膜的破碎模式受气液比的影响较大,随气液比的增加,液膜破碎模式由波动破碎逐步转变为湍流破碎。此外,清晰获得了自激振荡过程,分析了缩进室内部压力场及速度场分布特征。研究发现,随着气体压降增加,气体环缝出口会出现膨胀波和激波,形成一个“扇环形”的超声速流场区域;激波后气流分离,出现旋涡,形成局部高压区,旋涡中心随激波面周期性地上下移动,致使局部压力出现周期性振荡。展开更多
基金Aeronautical Science Foundation of China (99C5 10 91)
文摘An experimental study on the breakup of a conical liquid sheet from a pressure swirl atomizer was conducted by using a Particle Image Velocimetry (PIV) system. The variation of wavelength, wave speed and amplitude of wave versus liquid pressure was obtained. The results indicate that the cone half angle increases with liquid pressure. The stripped half wavelength liquid fragment seems to break into a series of drops immediately and no obvious contraction from liquid fragment to ligament is seen. The recorded images also show that both short and long wavelength waves exist simultaneously, and influence the breakup of the conical liquid sheet. The result of this study is useful for the purpose of developing and verifying the atomization model of spray produced by a pressure swirl atomizer.
文摘为了研究气液同轴离心式喷嘴缩进室内部非定常流动过程,采用Level Set和VOF(Volume of fluid)相耦合的方法,结合网格自适应技术对缩进长度为8mm的液体中心式气液同轴离心式喷嘴流动过程进行了数值仿真研究,计算得到了较为精细的液膜一次破碎过程、流场结构和压力振荡特性。结果表明:液膜的破碎模式受气液比的影响较大,随气液比的增加,液膜破碎模式由波动破碎逐步转变为湍流破碎。此外,清晰获得了自激振荡过程,分析了缩进室内部压力场及速度场分布特征。研究发现,随着气体压降增加,气体环缝出口会出现膨胀波和激波,形成一个“扇环形”的超声速流场区域;激波后气流分离,出现旋涡,形成局部高压区,旋涡中心随激波面周期性地上下移动,致使局部压力出现周期性振荡。
