翼前缘层板对流冷却结构的防热效果分析

针对飞行器高超声速飞行时严重的气动加热环境, 设计一种层板对流冷却结构对翼前缘进行热防护. 提出一种壁面冷却效率参数η, 并运用流固耦合的分析方法, 研究了对流冷却结构在特定条件下的冷却效果, 其中采用水冷时头部冷却效率η 值最低为0.25. 研究表明, 对流结构冷却效果与内部冷却槽道深宽比γ 有重要关系, η值随γ 的增大而增大至一个稳定值, 此时冷却效果达到饱和, 若此时γ 继续增加则可能出现不利于冷却的现象. 冷却效果η随着前缘头部半径的减小而减弱. 研究还表明, 当层板对流冷却结构和材料固定时, η 值随冷却剂流量增加而增大, 并逐渐趋近至一个稳定值, 而冷却槽道进出口压差急剧增大. 因此需要综合考虑提高流量给供给系统带来的压力, 选取最佳流量值以达到相对较好的冷却效果. 对于材料而言, 内部冷却通道和外部耐热层都应选择导热系数较高的材料, 能够强化结构传热增强冷却效果.

Research on convective cooling effect of leadingedge platelet of airfoil

A convective cooling platelet structure is a considered as thermal protection system to prevent the leading edge of airfoil from the serious aerodynamic heating. The cooling effect parameter η is proposed in this paper. By the use of fluid structure interaction method, the cooling effect of convective cooling structure is investigated under given condition. The minimum η that is 0.25 when the coolant is water occurs on the leading edge of airfoil head. The research shows that the η increases with the increase of channel aspect radio (γ) and reaches a stable value that indicates that the cooling effect is saturated. Situation unfavorable for cooling may occur if the γ keeps increasing. And the η decreases with the radio of airfoil's head decreasing. With coolant flux increasing, the η also increases to a stable value and the pressure drop between inlet and outlet increases rapidly when the structure and the material of the convective cooling platelet structure are fixed. Considering the pressure brought to the supply system due to the increase of flux, we should choose the optimal coolant flux value in order to obtain better cooling effect. Both the inner coolant groove and the external refractory protection should be of high thermal conductivity material which can strengthen the heat transfer of structure and enhance the cooling effect.