Design of shape morphing hypersonic inward-turning inlet using multistage optimization

Abstract

To make a compromise between compression efficiency and aerodynamic performance, a novel multistage optimization approach is proposed to improve the design of the shape morphing hypersonic inward-turning inlet. In the first stage, a parent flow inside an internal cone shaped from a special dual-inflection-point generatrix is optimized for the improvements of total pressure recovery and flow uniformity. The second stage is established to design the inlet lip shape via a single-objective optimization aiming to minimize the inviscid drag of the inlet. For rapidly predicting the inlet inviscid drag, we propose a streamline integral method characterized by high levels of computational efficiency and accuracy. The last stage is auxiliary to improve the practicability, mainly including an algebraic shape transition to regulate the inlet exit shape. Numerical results demonstrate that both the flow non-uniformity and the total pressure loss of the optimized parent flow are decreased significantly compared with the baseline parent flow. With the optimized lip shape, the inlet inviscid drag per unit mass flow rate is decreased as well. A simple quadratic function is the best choice to achieve the shape transition, which is beneficial to improve the inlet practicability with a less performance loss. With the multistage optimization framework, the improvements of the compression efficiency and the aerodynamic performance are both achieved and the balance between them is carefully manipulated as well. All the above demonstrates that the proposed optimization approach for the design of the shape morphing hypersonic inward-turning inlet is practical and efficient.