Efficient design-optimization for variable cross-section curved isolator in RBCC

The isolator, a critical component in RBCC engines, bridges the intake and combustion processes and plays a pivotal role in ensuring efficient performance across a wide speed range. However, designing variable cross-section curved isolators with optimal aerodynamic performance remains a significant challenge. This study investigates an efficient design-optimization methodology for such isolators. A convex optimization framework, incorporating sensitivity analysis of geometric parameters, is proposed and validated with multiple initial points. The aerodynamic performance of the isolator is evaluated across a wide speed range. The results demonstrate that: (1) A methodology for regulating the streamwise cross-sectional area distribution is established, enabling direct design of variable cross-section curved isolators; (2) A tailored optimization method, developed based on sensitivity analysis, reduces the number of iteration steps by nearly 87%, significantly improving design efficiency; (3) Compared to the baseline isolator, the optimized isolator achieves a remarkable reduction in total pressure loss by over 45% at the design point, while significantly enhancing total pressure recovery across the climb-type wide speed range trajectory. These findings not only provide valuable insights for the contour design of isolators in RBCC engines but also offer a robust framework for optimizing complex aerodynamic components in hypersonic propulsion systems.