分析了带Flade的自适应发动机工作机理,建立了发动机单外涵、双外涵、单外涵+第三外涵以及三外涵等4种工作模式的稳态性能数学模型,对带Flade的自适应发动机在典型工况下的稳态工作进行了数值仿真,对比分析了不同工作模式的工作特点.仿真结果表明,带Flade的自适应发动机能够根据不同工况和性能需求,改变工作模式,在一定范围内维持进气流量,更好的匹配进气道流通能力;单外涵+第三外涵工作模式应用于需要大推力的状态,三外涵模式应用于需要低耗油率的状态,双外涵工作模式则在涡轮前温度达到限制时可以产生更大的推力.

变循环发动机根据模式选择机构的打开和关闭有两种工作状态,在模态转换过程中,可能出现经过核心机驱动风扇压缩的气体一部分重新流回到核心机驱动风扇进口的现象.为分析变循环发动机中倒流现象对整机的影响规律,采用稳态性能仿真方法进行性能分析,完成了模拟稳定倒流现象的变循环发动机稳态模型建模.通过研究相关文献对倒流现象描述,从倒流现象产生、数学模型建立、倒流状态仿真三个方面对变循环发动机倒流现象进行阐述.通过采用一种向前引气的局部循环平衡被动收敛方法,实现发动机在设计点和非设计点计算过程中性能仿真.仿真结果表明:随着倒流流量的增加,风扇出口的流通能力降低,风扇工作点升高,裕度减小;核心机驱动风扇的流通能力提高,核心机驱动风扇工作点向下移动.

Mode transition (MT) is critical for adaptive cycle engine (ACE) to achieve mission adaptability. There are many constraints for the MT, making the control law difficult to design. At present, most design methods require manual analysis by researchers. When the design parameters of an engine are changed, it takes a lot of time to redesign the control law. What is more, most control laws need to adjust not only the mode selection valve (MSV), but also many other variable geometry components (VGCs) simultaneously, which makes the control system design complex and difficult. In this study, a general design method based on the particle swarm optimization method and the sensitivity calculation method is presented. This method can derive the control law for the MT without manual analysis, improving the efficiency of the design process. At most, one VGC needs to be adjusted during the change of state of the MSV, simplifying the control system. The fluctuation of thrust and airflow is less than 2%, and the surge margin of the compressors is higher than 10%, leading to a safe and stable MT. This method can adapt to the adjustment of the cycle parameters of the engine and the deviation of component performance, making it suitable for the engine performance design stage. It can also be applied to the design for other types of ACEs.

针对综合电力系统对涡扇发动机的影响进行分析.分析了电起动机与空气涡轮起动机的起动性能差异,采用功率较小的电起动机,通过调整控制规律能满足发动机的起动需求.分析了发动机在高压轴和低压轴进行功率提取对发动机性能的影响,低压功率提取在发动机稳定工作方面更有优势,适用于飞机短时大用电需求.对电动燃油泵性能优势进行分析,电动燃油泵可有效降低传统燃油泵在发动机节流状态因热回油造成的功率损失,以某型发动机为例更换电动燃油泵能够实现亚音速巡航耗油率约0.2％-0.5％的降低.

针对旋转部件等熵效率不连续的问题,提出使用换算扭矩代替等熵效率的方法,给出了旋转部件低转速特性拓展方法并获取了旋转部件的全转速特性.提出了可考虑点火及燃烧稳定性的燃烧室稳定性模型,最终建立了变循环发动机部件级整机起动模型.考虑了变循环发动机的8个可调参数,采用差分进化算法对变循环发动机在双外涵及单外涵模态下的起动过程进行了优化.结果表明:变循环发动机在双外涵及单外涵模态下的起动时间分别为17.2 s与12.8 s;双外涵模态下,需要调节燃油流量、喷管喉部面积与后可变面积涵道引射器外涵面积;单外涵模态下,需要调节燃油流量、喷管喉部面积与低压涡轮进口导叶面积;迎风来流马赫数为0.04时,变循环发动机在双外涵与单外涵模态时的起动时间比静止状态均减少0.2 s.

为了综合评价自适应变循环发动机相比常规涡扇发动机的性能优势,提出了从发动机耗油率降低和质量增加2个维度以及从发动机耗油率、飞机燃油消耗量和燃油效率之间关系的角度来评价自适应变循环发动机性能的2种方法.结果表明:发动机耗油率降低和质量增加之间存在某个平衡点,只有质量增加幅度小于耗油率降低幅度时,才能体现自适应变循环发动机的性能优势,并且飞机航程越长,越能体现自适应变循环发动机耗油率降低带来的优势;发动机耗油率、飞机燃油消耗量和燃油效率之间呈指数关系变化,当假设飞机巡航航程为3500 km、飞机升阻比为10.5时,自适应变循环发动机巡航耗油率相比常规涡扇发动机的降低1％,可使飞机燃油消耗量减少约1.9％,飞机燃油效率提高约2.4％.

为了研究双外涵变循环压缩系统的涵道流动匹配规律,发展了涵道流动的计算模型,对压缩系统模式转换过程中外涵道倒流问题的发生机理和影响因素进行了深入分析,总结了压缩系统的倒流判断准则,并基于简化计算模型和全三维计算结果对倒流判据进行了验证.研究结果表明,对于一定的压缩系统匹配状态,存在一个决定涵道匹配状态的临界核心机驱动风扇级(Core Driven Fan Stage,CDFS)总压比,当CDFS的实际工作压比高于临界压比时,压缩系统第二外涵道将发生倒流,反之则系统不倒流.复杂涵道系统内的流动损失和堵塞等特性对临界CDFS总压比有显著影响,为了准确判断压缩系统的匹配状态,需要对其进行精确模化.基于简化模型得到的压缩系统倒流临界线可以推广至全三维状态,提出的倒流判断准则具有较高的可靠性和可行性.

方案论证是航空发动机设计流程中的重要环节,本文提出了一种航空发动机总体方案论证耦合模型.该耦合模型可以对发动机压比、压气机流路、压气机效率、涡轮效率、涡轮前温度和涡轮冷气量进行快速评估,并给出调整建议.加速发动机方案论证的进程,缩短航空发动机设计周期.

Based on the commercial software Isight,a steady-state performance optimization method was proposed for a triple bypass variable cycle engine,and the optimization design platform was built.In this way,the function of the steady-state performance procedures was expanded,especially in the parameter study and optimization.Utilizing the platform,performance optimization of the typical engine working points was conducted,and the results were compared with the traditional method.With the help of the platform,the engine steady-state performance in different working conditions and various modes was analysed.The study results show that the Isight based optimization design platform could obviously improve the design efficiency and optimization precision,and fully exert performance advantage of triple bypass variable cycle engine.For getting the maximal thrust in any conditions,the best order of the mode selection is as follows as the inlet temperature raises:the first is single-bypass adding third-bypass mode,the second is single-bypass mode,the third is triple bypass mode and the last is double-bypass mode.

为了实现变循环发动机快速可靠的模态转换,发展了变循环发动机模态转换过渡态模型及控制规律设计方法.在变循环发动机动态数值仿真程序的基础上,针对模态选择阀与涵道引射器这两个模态转换过程中的关键变几何部件,建立了高精度的气流突扩局部损失模型.首次提出了可考虑模态选择阀堵塞对发动机性能影响的模态选择阀堵塞模型,消除了由于模型不精确造成的模态转换参数波动.在建立的变循环发动机数学模型的基础上,提出了基于直接推力控制技术的模态转换控制规律设计方法,考虑了变循环发动机的8个可调参数,采用差分进化算法对模态转换过程进行了优化.结果表明,本文提出的模态转换控制规律设计方法可以实现变循环发动机快速平稳的模态转换,双外涵转单外涵的参数变化规律与单外涵转双外涵的参数变化规律基本类似,推力在0.6s就稳定在目标推力值,其余参数大多在1.4s之后才趋于稳定.本文提出的变循环发动机模态转换控制规律设计方法还可应用于常规航空发动机的加/减速过渡态控制规律设计中.

In order to further improve the intercooled recuperated turbofan engine (IRT) performance, the possible high pressure turbine (HPT) cooling air bleeding schemes were analyzed. There are two HPT cooling air extraction sections, i.e. the high pressure compressor exit (forward to the recuperator cold section inlet) and the combustion chamber inlet (back from the recuperator cold section outlet). The analysis results indicate that, bleeding the HPT cooling air from the combustion chamber inlet has the potential to reduce the engine specific fuel consumption. And to determine the most suitable HPT cooling air bleeding scheme, effects of allowable turbine blade metal temperature, turbine cooling technology level, engine weight addition, different intercooler and recuperator effectiveness should be taken into account.