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在典型中小型航空发动机空气系统中,用于高压涡轮冷却、封严的空气一般需要经过离心压气机叶轮背腔,因此掌握以离心压气机叶轮背腔为代表的向心入流转静系盘腔内流动特点及压力分布是保证空气系统各项功能实现的关键。采用数值模拟方法对带有向心入流的转静系盘腔流动开展研究,研究不同来流条件下不同间距比的转静系盘腔流动特点及盘腔内压力分布。结果表明:在间距比G=0.01~0.2内,不同进口条件下盘腔内的流动均为Batchelor流型,即转盘与静盘具有独立边界层,边界层之间为核心区;当径向罗斯比数远小于1时,在核心区内流动满足径向平衡方程,此时盘腔内旋转比分布决定了盘腔内压力分布;对于满足径向平衡方程的此类盘腔,盘腔内流动由进口旋转比β_0、紊流参数λ_T、间距比G决定;进一步的,得到了不同β_0,λ_T,G下盘腔出口旋转比及核心区内旋转比变化规律,分析发现小间距比工况下核心区内旋转比满足5/7幂指数关系;大间距比工况下旋转比满足修正5/7幂指数关系,通过得到的旋转比关联式可以计算出盘腔内的压力分布。
In a typical small and medium aero-engine air system, the air used for cooling and sealing of high-pressure turbines generally needs to pass through the centrifugal compressor impeller back chamber. Therefore, the centripetal inlet hydrostatic disk chamber, represented by the centrifugal impeller back chamber, Flow characteristics and pressure distribution within the air system to ensure that the various functions to achieve the key. The numerical simulation is used to study the flow in a stationary static system with a centripetal inflow. The flow characteristics and the pressure distribution in the disk of a static system are studied under different flow conditions. The results show that the flow in the plate cavity under different inlet conditions is Batchelor flow with G = 0.01-0.2, ie, the turntable and the stator plate have independent boundary layers and the boundary layers are the core regions. When radial Rose When the ratio is far less than 1, the flow in the core area satisfies the radial equilibrium equation. At this time, the distribution of intracavity rotational velocity determines the pressure distribution in the intracavity. For this type of intracavity that satisfies the radial equilibrium equation, From the inlet rotation ratio β_0, the turbulence parameter λ_T and the pitch ratio G, the variation law of the outlet rotation ratio and the rotation ratio in the core area under different β_0, λ_T, G is obtained. It is found that the small- Core rotation ratio to meet the 5/7 exponential relationship; Large pitch ratio under the condition of the rotation ratio to meet the revised 5/7 power exponential relationship can be obtained by the rotation ratio correlation can be calculated within the disk pressure distribution.