双级涡轮增压活塞发动机螺旋桨推进系统部件法数学模型与飞行特性分析

Components level mathematical model of two-stage turbocharging reciprocating engine propeller propulsion system and analysis of its flying characteristic

对适用于高度为10~20km的中速、低速多用途飞行器的双级涡轮增压活塞发动机螺旋桨推进系统的特性计算方法进行了研究.引用涡轮发动机的部件法,建立基于各部件特性的代数数学模型,推进系统各部件工作点则由Newton法求解系统联合工作方程组得到.给出了方程组中的活塞发动机功率保持工作条件及增压器与活塞发动机联合工作条件,分析了推进系统功率保持工况和减功率工况的调节规律,及其对涡轮增压器工作线的影响.分析了推进系统总体及各部件的高度-速度特性.研究表明：该特性计算方法收敛快,一个工况点一般迭代5~6次即可;两个燃气旁通阀的调节规律不但可以满足推进系统的设计目标,同时还可对增压器工作点进行有效的优化调节;该特性计算方法可直接推广到更复杂的多级涡轮增压系统中.

A flying characteristic simulation method was studied for two-stage turbocharging reciprocating engine propeller propulsion system suitable for medium/high altitude low-speed long-endurance multi-role aerial vehicle systems at 10-20 kilometers height.With introduction of the simulation method for gas turbine engine with component models,and based upon component maps or algebraic equations,this method solved joint-working equations of the propulsion system by Newton iteration method to obtain co-operation points of the system.A full-power holding requirement and turbocharger-engine collaboration condition were stated.The regulating rules in both full-power holding mode and power lapse mode were analyzed.The influences of regulating rules on turbocharger operating lines were discussed.Finally,the altitude-velocity characteristics of the propulsion system and components were investigated.The research shows three results.This method enables rapid convergence and usually needs only 5-6iterations to obtain one operating point.The regulationscheme of two gas-bypass valves can not only meet the design objectives,but also allow effective adjustment to the operating points of the turbochargers.This method can be extended conveniently to the simulations of more complex multi-stage turbocharging systems.