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采用数值模拟和工程计算相结合的方法对HTV2第二次飞行试验的热环境进行了复现,发现在40km以下,翼前缘驻点线会发生边界层转捩,引起前缘热流比层流情况增加55%,最大热流达到11MW/m~2,烧蚀量约为3mm,前缘高热流导致法向应力超过碳布层与层之间的粘接强度,而纵向应力小于碳布拉伸破坏极限。因此本文认为,HTV2第二次飞行试验失利的原因主要是:烧蚀叠加应力破坏,即在翼前缘由于烧蚀导致多层碳布被烧破,从而在翼前缘沿展向驻点线出现较长的破损口,而法向应力导致碳布层与层之间的粘接失去作用,在气动力作用下,可能从烧破的地方开始将碳布掀起,严重影响气动性能,最终导致飞行器无法控制。
The thermal environment in the second flight test of HTV2 was reconstructed by the combination of numerical simulation and engineering calculation. It was found that the boundary layer transition occurred at the stagnation point line of the wing below 40 km, causing the frontal heat flux to be more laminar The situation increased 55%, the maximum heat flow reached 11MW / m ~ 2, ablation amount was about 3mm, the leading edge of high heat flow caused by the normal stress exceeds the bonding strength between carbon cloth layer and layer, while the longitudinal stress is less than carbon cloth stretching Destroy the limit. Therefore, this paper argues that the main reasons for the failure of the second flight test of HTV2 are: ablation superposition stress failure, that is, ablation in the leading edge of the wing leads to the burning of multi-layer carbon cloth, A longer breakage occurs, and the normal stress causes the bonding between the carbon cloth layer and the layer to be lost. Under the action of the aerodynamic force, the carbon cloth may be lifted off from the place where the burning is broken, which will seriously affect the aerodynamic performance and eventually lead to The aircraft can not control.