双级对转压气机多工况数值分析研究

以某双级对转压气机为研究对象,应用数值模拟方法获取不同转速、近喘振点内部流场细微结构,分析了不同工况上下游转子叶片表面流谱特点以及对转、逆压环境中上下游流场相互制约关系,为进一步优化设计对转压气机叶片提供依据。计算结果表明:该对转压气机在多种工况下两排转子来流攻角、落后角都较大,根部和尖部都有较强的分离流动;一级转子叶片表面分离线上游流动速度径向分量较大,可能导致该级转子尖部截面流动分离提前发生;下游转子对上游转子叶片尾迹的反向切割使得其不能按照自身发展规律向下游发展,一方面诱导了上游叶片尾缘附近流动分离,另一方面,对下游叶片来流攻角也产生一定的影响,导致下游转子叶片来流攻角进一步增大,从而加剧了二级转子的分离。

Numerical Investigation of Dual Stage Counter-Rotating ompressor for On-Design or Off-Design Conditions

To our knowledge,even in the rare papers in the open literature concerning counter-rotating compressor,we have not found detailed technical information about its flow structure.Our aim is to present the results of our effort to develop such information for a certain dual stage counter-rotating compressor to redesign and optimize the counter-rotating compressor blade.We have investigated by numerical simulation the detailed flow structure of a dual stage counter-rotating compressor near the surge conditions for each of several different rotating speeds.Both the characteristics of each flow pattern on each rotor surface and the interaction between the two counter-rotating rotors for on-design or off-design conditions have been analyzed in depth to optimize the design of counter-rotating compressor blades.The numerical results,given in Figs.1 through 4,show preliminarily that the inflow incidence and the deviation angle of the counter-rotating rotors are relatively large,implying that there exist separation flows on the blade to blade surface for both the hub and the tip.Taking into consideration both the numerical results given in Figs.1 through 4 and the discussion of the results shown in Figs.5 through 8,we are of the opinion that:(1) the radial velocity at the upstream of the separation line of the first row of rotor blades is relatively big;(2) the reversed sweep of the wake effect of the downstream rotor on the upstream rotor induces the separation near the trailing edge of the upstream rotor on the one hand and increases the inflow incidence of the downstream rotor on the other.