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为了研究黏度和导热系数对边界层内基本流和流动稳定性的影响,首先通过分析比较Sutherland公式和目前常用的Gupta等人的拟合关系式,建立了高温气体下黏度和导热系数的计算模型,并分别将Sutherland公式和新建立的计算模型应用于7组元化学平衡流的平板模型,在马赫数为10,16和20,飞行高度为30.5km等条件下分别对黏度和导热系数的模型进行比较.计算结果表明:在高温范围内,黏度和导热系数均影响着边界层的基本流、流动稳定性及转捩预测,且两者影响的趋势相反,黏度的增加、导热系数的减小都能使扰动的增长率变大,增长区变宽,转捩位置提前.
In order to study the influence of viscosity and thermal conductivity on the basic flow and flow stability in the boundary layer, a calculation model of viscosity and thermal conductivity under high temperature gas is established by analyzing and comparing the fitting formula of Sutherland formula and the commonly used Gupta et al. The Sutherland formula and the newly established calculation model were respectively applied to the flat model of 7-element chemical equilibrium flow. Under the condition of Mach number 10, 16 and 20 and flight altitude 30.5 km, the model of viscosity and thermal conductivity The results show that both the viscosity and thermal conductivity of the boundary layer affect the basic flow, the flow stability and the transition prediction in the high temperature range, and the trend of the two is opposite, the viscosity increases and the thermal conductivity decreases Can increase the rate of increase of disturbance, widen the area of growth, and shift the location ahead of schedule.