双S弯喷管的流固耦合特性研究

为了明晰S弯喷管的流固耦合特性,数值模拟了流固耦合作用下双S弯收敛喷管的结构变形特征及其内/外流特性。结果表明：S弯喷管的圆转方弯曲构型产生了非均匀的流场分布,并增强了结构的弹性特征,它们通过交换气动载荷与变形位移数据形成了S弯喷管流固耦合的作用机理。在气动载荷作用下,S弯喷管沿Y向的最大变形位移为25.3mm,它位于喷管出口上壁面的中心位置。当喷管的结构变形稳定时,第二弯转弯处下壁面的气流加速至局部超音速,壁面静压大幅降低；第一弯下游上壁面附近形成了气流分离区；喷管出口喷流沿轴向向上偏转。流固耦合作用导致S弯喷管的流量系数减小0.6%,推力系数降低1.8%。矩形截面与弯曲构型是影响S弯喷管流固耦合特性的主要几何特征,其中矩形截面能够显著增大喷管的变形位移；S形弯曲构型虽然能够有效抑制变形特征,但它导致喷管多个区域出现变形,喷管的结构变形分布变得更加复杂。

Fluid-Structure Interaction Characteristic of Double Serpentine Nozzle

In order to clarify the fluid-structure interaction characteristics of serpentine nozzle, the structural deformation features as well as internal flow and external jet characteristics of double serpentine convergent nozzle under the action of fluid-structure interaction had been numerically simulated. Results are obtained as follows: The non-uniform flow fields are produced by round inlet transiting rectangular outlet curved configuration of serpentine nozzle, which strengthens the elasticity of its own structure at the same time. Then, the coupling mechanisms of serpentine nozzle are formed by the transferring aerodynamic force and deformable displacement data between flow field and structure. The maximum value of deformable displacement of serpentine nozzle exerted by aerodynamic loads is 25.3mm along the Y direction, which is located at the center of the upper wall of the nozzle outlet section. When the structural deformation is stable, the airflow on the lower wall of the second inflection accelerates to local supersonic where the wall static pressure is greatly reduced, the flow separation region is presented around the upper wall downstream of the first inflection, and the plume core region near nozzle exit deflects upward along the axial direction. The discharge coefficient and thrust coefficient decrease by 0.6% and 1.8% respectively under the action of fluid-structure interaction. Rectangular cross-section and S-shaped curved configuration are the main geometric features which has an effect on the fluid-structure interaction characteristics of serpentine nozzle. The rectangular cross-section can significantly enlarge the structural deformation features of the nozzle. The S-shaped curved configuration can effectively suppress deformation features while it generates several deformable regions on the serpentine nozzle. Thus, the distributions of nozzle structural deformation become more complex.