OPTIMIZATION AND ANALYSIS OF THE LEADING EDGE SHAPE FOR HYPERSONIC AIRPLANES BASED ON DOE METHODS

By taking a Blend-Wing-Body configuration with dual flanking inlets layout as the baseline, an aerodynamic shape optimization study for the leading edge of the vehicle is carried out.An increment-based method is developed to parameterize the leading edge, and the uniform design method is taken as the optimization driver.Totally 31 configurations with different leading edge shapes are generated, and then the aerodynamic performance of all configurations are evaluated by computational fluid dynamic simulation in the cruising conditions of Mach 6, flight altitude 26 km, and flight angle of attack 4°.Numerical results show that the relative variations of the lift and the drag coefficients in whole design space are 21.3% and 31.8%, respectively.Consequently, the relative variation of the lift-to-drag ratio is about 10.63%.In contrast, the maximal value of the relative position transition for the longitudinal pressure center is only 3.87%.Besides, the results also indicate that there is a proportional relationship between the vertical project area and the lift or drag coefficients. Finally, the effect of the leading edge deformation on the aerodynamic characteristics is analyzed on the basis of the results, and some primary rules are concluded.A concave shape of the leading edge is benefit to the improvement of the lift-to-drag ratio, while a convex one leads to a large lift coefficient.