Approximate Prediction for Aerodynamic Heating and Design for Leading-edge Bluntness on Hypersonic Vehicles

摘要

During the process of preliminary and conceptual design of hypersonic vehicles, predicting surface friction as well as heat flux is crucial to the design of the thermal protection system (TPS) and optimization of aero-thermodynamics. This paper primarily focuses on two aspects. Firstly, an engineering code has been successfully developed to compute the approximate heating rates of general three-dimensional hypersonic vehicles at angles of attack using unstructured grids for perfect gas. A three-dimensional linear description of surface and flowfield is proposed, based on which an improved axisymmetric analog method is developed, which calculates inviscid surface streamlines and metric coefficients over the body. An implicit surface fitting method is introduced to fit the primary curvatures at stagnation point and a robust marching scheme for calculating heating rates downstream of stagnation region is developed. The proposed engineering approach is verified through a spherically blunted cone and a double ellipsoid, satisfactory agreement between calculation results and wind tunnel experimental results is found. Secondly, a quasi-waverider wing-body model is constructed, the sharp leading-edge of the wing is blunted using circular tips with distinct values of radius, the bluntness effect on the aerodynamic performance is investigated, which would be of vital importance for future work in designing and optimizing the shape of the blunt leading-edge on hypersonic vehicles.