A new hypersonic Mach 12 nozzle has been designed and manufactured for a large-scale expansion tube. The nozzle design goals were to produce a Mach 12 flow, with a core flow diameter of at least 300 mm and a maximum exit flow angle non-uniformity of less than $${2}^{\circ }$$ 2 ∘ . The nozzle has been designed by coupling a RANS CFD solver with a parallel simplex algorithm to solve the computationally expensive optimisation problem. Novel aspects of this analysis are that it addresses nozzle optimisation specifically for scramjet test flows, characterised by high pressures and thick boundary layers. A new MPI implementation of a block-marching technique is used to solve the flowfield, which is optimised with a parallel Nelder–Mead algorithm. The validity of the objective functions is discussed through a robust bootstrapping analysis, and off-design performance of the nozzle is also characterised. The analysis demonstrates that the optimised contour achieves the design objectives and has excellent off-design performance. Initial commissioning experiments confirmed the results of the numerical analysis. Despite the final operating conditions being slightly off-design, the nozzle was able to produce an experimental core flow exceeding the numerical predictions. Indeed, the manufactured nozzle, 2.8 m long, with an exit diameter of 573 mm, has been shown experimentally to produce a core flow size of 360 mm, enabling full-scale Mach 12 scramjet experiments.

中文翻译：

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使用并行单纯形算法的膨胀管喷嘴设计

为大型膨胀管设计并制造了一种新的高超音速 12 马赫喷嘴。喷嘴的设计目标是产生 12 马赫的流量，核心流直径至少为 300 毫米，最大出口流动角不均匀性小于 $${2}^{\circ}$$2 ∘ 。喷嘴的设计是通过将 RANS CFD 求解器与并行单纯形算法耦合来解决计算成本高的优化问题。该分析的新颖之处在于它专门针对超燃冲压发动机测试流进行喷嘴优化，其特点是高压和厚边界层。块行进技术的新 MPI 实现用于求解流场，该流场使用并行 Nelder-Mead 算法进行了优化。通过稳健的自举分析讨论了目标函数的有效性，喷嘴的非设计性能也有特点。分析表明，优化后的轮廓达到了设计目标，并具有出色的设计外性能。初始调试实验证实了数值分析的结果。尽管最终的操作条件略有偏离设计，但喷嘴能够产生超过数值预测的实验核心流量。事实上，制造的喷嘴长 2.8 m，出口直径为 573 mm，已通过实验证明可产生 360 mm 的核心流尺寸，从而实现全尺寸 12 马赫超燃冲压发动机实验。初始调试实验证实了数值分析的结果。尽管最终的操作条件略有偏离设计，但喷嘴能够产生超过数值预测的实验核心流量。事实上，制造的喷嘴长 2.8 m，出口直径为 573 mm，已通过实验证明可产生 360 mm 的核心流尺寸，从而实现全尺寸 12 马赫超燃冲压发动机实验。初始调试实验证实了数值分析的结果。尽管最终的操作条件略有偏离设计，但喷嘴能够产生超过数值预测的实验核心流量。事实上，制造的喷嘴长 2.8 m，出口直径为 573 mm，已通过实验证明可产生 360 mm 的核心流尺寸，从而实现全尺寸 12 马赫超燃冲压发动机实验。