Study on aerodynamic characteristics and overall scheme design of multi-position coordinated jet for lifting-body vehicle

Long-endurance, high-Mach, high-overload, and reusable capabilities have emerged as key development directions for future high-speed vehicles. These trends impose increasingly stringent requirements on the aerodynamic performance and thermal protection systems of high-speed vehicles. As an efficient approach for drag reduction and heat attenuation, active jet flow has become a research hotspot. Taking the lifting-body vehicle as the research object, this paper aims to address the bottleneck problem of drag reduction limit of the standalone forebody opposing jet, investigates the flow field modification mechanism, aerodynamic and aerothermal characteristics and engineering scheme design of multi-position coordinated jet flow, and reveals the coupled drag reduction and heat attenuation mechanism of forebody opposing jet and fuselage lateral jets. First, an overall scheme of the multi-position jet delivery system for the vehicle is proposed. On this basis, numerical simulations of the jet flow field under different jet parameters are carried out to analyze the underlying mechanisms of drag reduction and heat attenuation. A systematic study and analysis are performed on the pressure ratio combinations and jet orifice on-off combinations; comparisons are made among different combination modes and schemes, with the goal of achieving superior drag reduction and heat attenuation performance at lower mass flow consumption. The results indicate that multi-position coordinated jet flow can further improve the drag reduction rate of the vehicle while ensuring effective heat attenuation. Specifically, activating two rows of jet orifices and adopting the jet strategy of high pressure ratio at the forebody coupled with low pressure ratio at the fuselage can achieve an overall drag reduction of 7.58% and heat attenuation of 10.29% for the vehicle, thus enhancing its comprehensive performance. The research findings lay a solid foundation for the further engineering application of active jet flow.