面向推力优化的并联TBCC组合喷管设计方法

Optimum design method oriented thrust for over-under TBCC combined nozzle

针对宽速域飞机机体/推进的强耦合,提出一种在给定几何尺寸约束下面向推力优化的并联涡轮冲压组合发动机(TBCC)组合喷管设计方法。通过理论分析和数值模拟相结合的手段,实现了宽速域组合喷管在欠膨胀和过膨胀流动状态下涡轮/冲压流道面积膨胀比的优化分配。在研究的涡轮/冲压落压比范围内,相比基准组合喷管,面向推力优化设计得到的组合喷管均能具有更高的推力性能,两者综合推力系数的差异在涡轮单独工作的过膨胀流动状态尤为明显,通过推力优化可使得马赫数为0.2和3时的推力系数分别提高4.89%和4.14%。推力优化喷管的升力和俯仰力矩随飞行马赫数的变化幅度相比基准喷管分别减小了33%和47.3%,这可以有效减小机体/推进耦合下全机气动焦点的变化范围,有利于减小宽速域飞机配平阻力并降低飞行器操稳控制难度。

Considering the requirements on integration of aircraft/engines,a design method of overunder turbine based combined cycle engine(TBCC)nozzle oriented thrust optimization under a given geometric constraint was proposed.The optimal allocation of the area expansion ratio of the turboengine/ramjet nozzle at under-expansion and over-expansion state was realized by means of theoretical analysis and numerical simulation.Within the range of turbo-engine/ramjet pressure-drop-ratio,the TBCC nozzle designed for thrust optimization can achieve higher thrust performance than the baseline nozzle,and the difference in composite thrust coefficient was particularly obvious under the over-expansion state,where the thrust coefficients at Mach number of 0.2 and 3 can be increased by 4.89% and 4.14%,respectively,through thrust optimization.Furthermore,the lift force and pitching moment of thrust optimization nozzle changing with the Mach number were 33% and 47.3% smaller than those of the baseline nozzle,which can effectively reduce the range of aerodynamic focus of the whole aircraft,helping to reduce the trim resistance of wide-speed-range aircraft and the difficulty of flight control.