论文标题
双铃火箭喷嘴中的被动流分离控制
Passive flow-separation control in a dual-bell rocket nozzle
论文作者
论文摘要
在高雷诺数和海平面模式下的亚尺度冷气中的延迟的分离涡流模拟，以喷嘴压力比NPR = 45.7进行。在这种状态下，过度扩展的流动在拐点处表现出对称和受控的流动分离，即两个铃铛之间的连接，导致相对于传统的铃铛喷嘴产生了低含量的空气动力学侧负荷。在频域中分析了喷嘴壁压签名，并将其与文献中有关相同几何和流量条件的实验数据进行了比较。时间和空间上的傅立叶光谱（方位角波数）显示出与对称冲击运动相关的持续音调。不对称模式仅被冲击和湍流结构稍微激发。侧载幅度的低平均值与实验非常吻合，并确认拐点会抑制分离震和分离的剪切层之间的空气声相互作用。
A delayed detached eddy simulation of a sub-scale cold-gas dual-bell nozzle flow at high Reynolds number and in sea-level mode is carried out at nozzle pressure ratio NPR=45.7. In this regime the over-expanded flow exhibits a symmetric and controlled flow separation at the inflection point, that is the junction between the two bells, leading to the generation of a low content of aerodynamic side loads with respect to conventional bell nozzles. The nozzle wall-pressure signature is analysed in the frequency domain and compared with the experimental data available in the literature for the same geometry and flow conditions. The Fourier spectra in time and space (azimuthal wavenumber) show the presence of a persistent tone associated to the symmetric shock movement. Asymmetric modes are only slightly excited by the shock and the turbulent structures. The low mean value of the side-loads magnitude is in good agreement with the experiments and confirms that the inflection point dampens the aero-acoustic interaction between the separation-shock and the detached shear layer.
