The dual-throat vectoring nozzle is an efficient technique utilizing less high-pressure secondary streams to control mainstream deflections flexibly. In this article, three-dimensional Reynolds-averaged Navier–Stokes simulations were performed using a commercial computational fluid dynamics program, and the numerical methods applied in this study were validated through comparison with the experimental results. Two parameters of the slot injector have been investigated, namely the incident angle of the secondary stream and the slot length-to-width ratio. Critical performance parameters have been quantitatively analyzed, involving the pitching angle, injected mass flow ratio, system resultant thrust ratio, and resultant pitching thrust efficiency. Furthermore, visual flow-field features are expounded using Mach number contours on the center-plane, Mach number contours on various slices, and streaklines. Some meaningful conclusions are drawn herein. The flow field in this three-dimensional dual-throat nozzle is not fully symmetric based on the reference of the center-plane. Consequently, a full domain is essential to capture the flow characteristics accurately, instead of a half domain. Although the pitching angle for the secondary stream incidence angle of 120° is the highest, comprehensive characteristics in terms of resultant pitching thrust efficiency and system resultant thrust ratio for 150° are more outstanding. The pitching angle, system resultant thrust ratio, and resultant pitching thrust efficiency increase with an increase in the slot length-to-width ratio for a constant secondary stream mass flow rate. Under the circumstance of a constant injection pressure ratio, the pitching angle increases with an increase in the slot length, whereas system resultant thrust ratio and resultant pitching thrust efficiency decline with an increasing slot length.

Graphic abstract

中文翻译：

---

三维双喉喷嘴推力矢量控制的可视化与分析

双喉矢量喷嘴是一种有效的技术，它利用较少的高压次要流来灵活地控制主流偏斜。在本文中，使用商业计算流体动力学程序进行了三维雷诺平均Navier-Stokes模拟，并通过与实验结果进行比较验证了本研究中应用的数值方法。已经研究了狭缝喷射器的两个参数，即二次流的入射角和狭缝的长宽比。已对关键性能参数进行了定量分析，包括俯仰角，注入质量流量比，系统合成推力比和合成俯仰推力效率。此外，使用中心平面上的马赫数等高线阐述了视觉流场特征，马赫数轮廓在各种切片和条纹上。本文得出一些有意义的结论。基于中心平面的参考，此三维双喉喷嘴中的流场不完全对称。因此，完整域对于精确捕获流量特性至关重要，而不是半域。尽管二次流入射角的俯仰角为120°最高，但在150°的总俯仰推力效率和系统总推力比方面，综合特性更为突出。对于恒定的二次流质量流量，随着缝隙长宽比的增加，俯仰角，系统合成推力比和合成俯仰推力效率也会增加。在恒定注射压力比的情况下，

图形摘要