NACA埋入式进气口气动特性试验设计优化

为了优化(美国)国家航空咨询委员会(National Advisory Committee for Aeronautics,NACA)埋入式进气口气动特性,基于计算流体力学(computational fluid dynamics,CFD)数值方法,以阻力、总压恢复系数、出口质量流量和出口马赫数为性能指标,对3个关键几何参数进行了试验设计(design of experiments,DoE).基准工况结果表明,在进气口斜坡侧边靠近主流处有轴向涡产生.DoE结果表明,斜坡角度对性能指标影响大,斜坡扩张角角影响小,出口转折半径对阻力和出口质量流量影响大,且斜坡角度一定时折转半径越小越好.斜坡角度越小,前缘位置马赫数越小,涡管越长,同一截面速度分布越均匀,因此总压恢复系数和出口质量流量越大,且出口气流不均匀度小,气动性能佳.

DoE design for a NACA air intake based on numerical methods

The DoE design combined with numerical simulations was employed to optimize the aerodynamic characteristics of a NACA air intake. The drag force, total pressure recovery coefficient, mass flow rate and Mach number at the outlet were used to evaluate the performance. Three critical geometric parameters were considered as variables. Results of the baseline case indicated that axial vortexes were formed near the side edge close to the ramp wall. DoE analysis indicated that above four parameters were severely influenced by the ramp angle, while the ramp divergence angle had an opposite effect. A small radius of the turning channel is beneficial to enhance the pressure recovery coefficient and mass flow rate. Mach number at the outlet declines and the velocity uniformity at a certain section increases with decreasing ramp angle value. Meanwhile, larger total pressure recovery coefficient, mass flow rate and vortex tube length are acquired. Thus the aerodynamic performance of this air intake can be improved.