齿轮传动旋转流场对喷油射流甩离的影响

针对啮入侧喷油方式,运用计算流体动力学(CFD)方法,建立了高速旋转流场中喷油射流模型。通过仿真计算发现高速流场对射流具有甩离效应,当对啮合齿轮进行喷油时,射流具有向小轮方向甩离的趋势,其甩离程度随着转速和模数增加而增大;滑油的出口速度越大,抵抗旋转流场甩离效应的能力越强。通过理论分析深入揭示了旋转流场对射流甩离效应的成因机理。最后,通过搭建射流甩离相似试验台,验证了分析结论。

高速齿轮的气障特性分析

利用计算流体动力学方法,建立齿轮高速旋转在周围产生的流场与压力场计算模型,对不同的齿轮工况参数进行了计算与分析。在此基础上,建立齿轮喷油润滑的二相流模型,对喷油参数与齿轮工况的匹配进行研究,并对齿轮旋转压力场的计算进行了仿真验证。结果表明,齿轮转动时会在周围形成气体压力场,对喷油射流产生阻碍作用,造成轮齿润滑与冷却失效。本文的研究成果将用于指导新一代高性能齿轮的喷油润滑设计。

Breakup Structure of Two-phase Jets with Various Momentum Flux from a Porous Injector

Spray structure and atomization characteristics were investigated through a comparison of a porous and a shear coaxial injector. The porous injector shows better atomization performance than the shear coaxial injector. To in- crease atomization performance and mixing efficiency of two-phase jets, a coaxial porous injector which can be applicable to liquid rocket combustors was designed and tested. The characteristics of atomization and spray from a porous and a shear coaxial injector were characterized by the momentum flux ratio. The breakup mechanism of the porous injector is governed by Taylor-Culick flow and axial shear forces. Momentum of injected gas flow through a porous material which is composed of sintered metal is radically transferred to the center of the liquid column, and then liquid column is effectively broken up. Although the shapes of spray from porous and shear co- axial jets were similar for various momentum ratio, spray structures such as spray angle and droplet sizes were different. As increasing the momentum flux ratio, SMD from the porous injector showed smaller value than the shear coaxial injector