Multidisciplinary Study Of Key Components In Hypersonic Flight Vehicle

The flight environment experienced by air-breathing hypersonic vehicles can give rise to serious fluid-structural-thermal coupling problems, which highlights the necessity to conduct integrated multidiscipline analysis targeting at its key components for the aim of designing vehicle structures and flight control laws. In this paper, A finite-volume-based CFD solver FLUENT is adopted to solve the unsteady Reynolds average Navier-Stokes equations. ABAQUS, a finite-element-method-based CSD solver, is employed to compute the structural elastic deformation and heat conduction. A two-way interaction between different fields is accomplished by mesh-based parallel-code coupling interface(MpCCI), which controls the coupling process and handles the exchange of coupling quantities. Three components of the air-breathing hypersonic vehicle are chosen and related multidisciplinary investigations are conducted.Firstly, the accuracy of the fluid-structural coupling procedure is validated for the flutter of a flat plate in supersonic flow, and the accuracy of the fluid-thermal coupling procedure is validated by comparing with experimental data for Mach 6.47 flow over a cylindrical leading-edge model.Secondly, the interaction between the slide plate(mounted at the end of SERN upper ramp) and the surrounding flow-field is investigated. Plate’s vibrations and nozzle aerodynamic performances with different slide plate lengths(150, 180mm) and thickness(5, 7mm) were obtained. The numerical results indicate that, under the same plate thickness(5mm), shorter plate possesses lower aerodynamic performance(with a decrease of 9.9% in lift) and better dynamic characteristic(with a decrease of 44.7% in response time). Under the same plate length(180mm), better aerodynamic and dynamic performance can be achieved when the plate thickness is increased, namely, the lift is increased by 0.98%, the pitch moment difference is decreased by 10.5% and the response time is reduced by 40.4%.Thirdly, the aeroelastic behavior of the splitter plate in TBCC exhaust system and the corresponding dynamic flow features are investigated. The results show that the plate vibrates with decaying amplitude and reaches a dynamic stable state eventually. The thrust, lift and pitch moment of the TBCC exhaust system are increased by 0.68%, 2.82% and 5.86%, respectively, compared with the corresponding values in steady state which does not take into account the fluid-structure interaction effects.Finally, fluid-thermal interaction simulations are conducted on a blunt body equipped with a spike with variable length(L/D=1, 1.5, 2, 2.5). The results show that, blunt body with a longer spike yields a better dynamic thermal performance, that is, a lower peak temperature on blunt forebody surface and a slower temperature rise both on forebody surface and inside the structure can be obtained, indicating that longer spike is preferred in terms of thermal protection. In addition, various levels of drag coefficient drop can be observed during the coupling process. A maximum decrease of 5.7% is achieved among the investigated models.