考虑空腔的高超声速多流动区域同步数值模拟

A synchronized method for multi-regional simulation in hypersonic flow with inclusion of convection in a contained cavity

先进的高超声速飞行器具有薄壁空腔结构,在飞行过程中受热会产生空腔内气体流动现象,从而影响流场和结构的温度分布。采用数值方法准确模拟高超声速流场、结构温度场和空腔内流动对热结构分析是很有必要的。以研究空腔流动对结构温度分布影响为目的,发展了一种适用于多流动区域流场/结构温度场耦合问题的同步计算方法,并以高超声速带空腔结构物体为例,数值研究了其外部气动热/结构热传导引起的空腔热对流问题。以已发展的高超声速外流场/结构温度场同步计算方法为基础,为了进一步考虑空腔内低速流场,采用了预处理矩阵方法。在流场与结构温度场的交界面两侧分别引入虚拟单元,从而高效地实现相邻场之间物理信息交换。首先通过标准算例验证了方法在求解单独气动热/结构热传导问题以及空腔自然对流问题中的准确性。进而对封闭和带有开孔的两种高超声速运动圆环分别进行多流动区域同步数值模拟。计算结果表明,由于结构温度不均匀引起的空腔内热对流反之也会对结构温度场分布产生轻微的影响。在空腔内气体流动的影响下,封闭圆环的前缘温度在35 s内最多下降0.8%左右。对于带开孔空腔的圆环,其孔壁周边温度在0.5 s内能够超过外流前缘驻点温度。

Hypersonic aerodynamic heating causes gas flow in many advanced hypersonic vehicles with contained cavity.It is necessary to accurately simulate hypersonic flow field,structure temperature field,and cavity flow by numerical method for thermal structure analysis.In this paper,a synchronized method for multi-regional simulation in hypersonic flow is developed.Particularly,a hypersonic moving object containing a cavity is our major concern,where the thermal convection in the cavity caused by the external aerothermal/structural heat conduction is investigated.Based on the previously developed synchronized method for external hypersonic flow/structural temperature field coupling,the preconditioning matrix method is adopted in order to further consider the low-speed cavity flow.The virtual boundary cells are introduced on both sides of the interface between the flow field and the structural temperature field,so that the physical information exchange between adjacent fields can be efficiently realized.The present method is first validated through two benchmark cases,then it is further applied to two hypersonic moving annuli with closed and perforated cavities.For the both two annuli,the computed results show that the cavity flows caused by uneven distributions of structural temperature could have a slight influence on the structural temperature field in turn.Under the influence of convective flow in the cavity,the leading edge temperature of the closed ring in 35s decreases by about 0.8%.For the annulus with perforated cavity,the temperature around the hole wall exceeds the stagnation point temperature at the leading edge of the outflow within 0.5 s.A numerical method for simulating the structure heat conduction of hypersonic vehicle considering cavity flow is provided.