畸变指数比例可调的组合插板数值模拟研究

Numerical Simulation on Combinational Baffle with Adjustable Ratio of Distortion Indexes

利用畸变发生器开展进气总压畸变试验研究具有较好的安全性与经济性,是航空发动机稳定性评估的重要技术。现有畸变发生器在稳、动态畸变指数比例的调节上具有一定的不足,较大地制约了发动机稳定性的评估。针对该局限性,本文创新设计可调组合插板畸变发生器,用于实现稳、动态畸变指数比例的调节。同时,采用应力混涡模拟(SBES)模型进行数值模拟,旨在提高大尺度分离涡结构的捕捉能力。研究发现,与基于雷诺平均N-S (RANS)方程的模型相比,采用SBES模型模拟的稳、动态畸变指数具有更高的准确度。此外,可调组合插板畸变发生器产生的稳态畸变指数占比可达约19%~58%,相较于单插板约50%的稳态畸变指数占比有了较大范围的拓宽。研究证实了本文设计的可调组合插板畸变发生器具有稳、动态畸变指数比例可调的能力。

The use of the inlet total-pressure distortion generator in engine testing has better safety and economic performance, which is an important technique for the assessment of engine stability. The existing distortion generators have some deficiencies in the adjustment of the ratio of steady-state and time-variant distortion indexes, and the assessment of engine stability is greatly restricted. For this reason, a variable combinational baffle distortion generator was developed, which can adjust the ratio of the distortion indexes. To improve the capability to capture the large scale detached eddy structures, the stress-blended eddy simulation(SBES) model was adopted to simulate. The results show that compared with turbulence models in Reynolds-averaged Navier-Stokes(RANS) equations, steady-state and time-variant distortion indexes which are simulated by using the SBES model are more accurate. The ratio of steady-state distortion index generated by the variable combinational baffle distortion generator is about 19% to 58%. The range is extended significantly compared with the single-baffle distortion generator, in which the ratio is about 50%. The variable combinational baffle distortion generator can adjust the ratio of distortion indexes.