几何参数对V字形钝前缘气动热特性影响

针对三维内转式进气道V字形唇口部位气动热载荷严酷的问题, 将唇口简化为V字形钝前缘, 在来流马赫数6条件下, 采用数值模拟并辅以激波风洞实验, 研究了气动热随前缘几何参数的变化规律. 结果表明, 在半径比R/r (根部倒圆半径R和前缘钝化半径r之比)和半扩张角β的联合作用下, V字形根部主要出现三种激波反射类型, 其壁面热流峰值的位置和大小均差异明显. 在(R/r, β)几何参数空间中, 当R/r和β都相对较小时, V字形根部发生异侧激波规则反射, 超声速气流冲击驻点附近壁面, 并产生极其严酷的第一类中心热流峰值, 最高可达相同钝化半径圆柱驻点热流的12倍. 当R/r或β较大, V字形根部发生马赫反射时, 异侧超声速射流对撞以及激波/边界层干扰分别导致了第二类中心热流峰值和外侧热流峰值, 其严酷程度仅次于第一类中心热流峰值, 采用R/r和β建立了第二类中心热流峰值和外侧热流峰值强弱转变的边界. 当R/r充分大, V字形根部发生同侧激波规则反射时, 第二类中心热流峰值和外侧热流峰值都减小至相同钝化半径圆柱驻点热流的水平. 

EFFECTS OF GEOMETRY PARAMETERS ON AEROTHERMAL HEATING LOADS OF V-SHAPED BLUNT LEADING EDGES

Severe aerothermal heating loads are commonly encountered on the V-shaped cowl lips of three-dimensional inward-turning inlets. To reveal the effects of the geometry parameters on the aerothermal heating loads, a simplified model called V-shaped blunt leading edge is employed, and numerical simulations and shock tunnel experiments are performed at a freestream Mach number of 6. The results indicate that with the combined effects of the R/r (i.e., the crotch rounding radius R to the blunt radius r) and the half-span angle β, three types of shock reflections are generated at the crotches, leading to obvious differences in the position and intensity of the heating peaks on the wall. In the geometric parameter space (R/r, β), the regular reflection occurs at the crotch when R/r and β are small. The supersonic jet impingement near the stagnation point causes the first type of central heating peak, which can reach up to 12 times stagnation heat flux of a cylinder with the same r. For larger parameter values of R/r and β, the Mach reflection occurs at the crotch. The collision of the robust jets and the shock wave/boundary layer interactions result in the second type of central heating peaks and outermost heating peaks, respectively, and these peaks are less than the first type of central heating peaks. An intensity transition criterion between the second type of central heating peaks and outermost heating peaks is established in terms of R/r and β. When R/r is large enough, the regular re?ection from the same family occurs at the crotch. Correspondingly, both the second type of central heating peaks and outermost heating peaks decrease significantly.