Research on windmill starting characteristics of MTE-D micro turbine engine

Micro turbine engine (MTE) is an important kind of propulsion system for miniature unmanned aircraft or missiles, because of its better high-speed performance (than propeller propulsion) and higher propulsion efficiency (obviously than rockets). Windmill start is a common air-starting mode used in micro turbine engine. The windmill starting characteristics are important to the practical use of micro turbine engine. In this paper, the windmill starting characteristics research for a 12 cm diameter (MTE-D) micro turbine engine is carried out by experiment and numerical simulation. The characteristic of rotor mechanical losses at low-speed condition is stud- ied, and the engine common working line of windmill starting process is obtained. Based on the engine windmill characteristics, the propane ignition characteristics under different inflow conditions are researched, and the envelope of propane ignition and propane flameout is determined. The experimental research of fuel supply and ignition characteristics is completed, and the envelope of fuel supply and ignition is obtained. The windmill stage, propane ignition stage, fuel ignition stage and acceleration process from idling-speed to 80% full speed of MTE-D micro turbine engine is optimized, and the optimization windmill starting parameters are collected. The successful wind-mill starting experiment under this condition with engine speed up to 80% full speed indicates that these starting parameters are reasonable. All the starting parameters of MTE-D micro turbine engine obtained in this work are dimensionless parameters, and the conclusions obtained in this study have some reference to other micro turbine engines with the similar structural form and starting process.     

世界航空发动机高压涡轮导向器研究综述

针对航空发动机涡轮气冷导向叶片的结构特征,结合国内外相关工作的研究状况,本文从多方面对高压涡轮气冷导向叶片结构设计与制造技术所取得的研究成果进行了总结和分析,重点介绍了高压涡轮气冷导向叶片的结构特点与制造工艺等。     

Active generalized predictive control of turbine tip clearance for aero-engines

Active control of turbine blade tip clearance continues to be a concern in design and control of gas turbines. Ever increasing demands for improved efficiency and higher operating temperatures require more stringent tolerances on turbine tip clearance. In this paper, a turbine tip clearance control apparatus and a model of turbine tip clearance are proposed; an implicit active generalized predictive control （GPC）, with auto-regressive （AR） error modification and fuzzy adjustment on control horizon, is presented, as well as a quantitative analysis method of robust per- turbation radius of the system. The active clearance control （ACC） of aero-engine turbine tip clear- ance is evaluated in a lapse-rate take-off transient, along with the comparative and quantitative analysis of the stability and robustness of the active tip clearance control system. The results show that the resultant active tip clearance control system with the improved GPC has favorable steadystate and dynamic performance and benefits of increased efficiency, reduced specific fuel consump- tion, and additional service life.     

高速轴流压气机叶尖流动特性试验

为研究压气机转子叶尖流动特性,通过高频动态压力传感器测量其第一级转子壁面静压,录取了多个换算转速下的试验数据,并采用等相位平均方法处理。结果表明:相对换算转速0.6以上槽道激波明显,且随着转速的升高,激波强度增加;叶尖泄漏流动明显,叶片前缘位置最强烈,沿流向逐渐减弱,影响了近1/2弦长、1/3倍叶栅流场;0.7及以上高转速状态下,在叶栅弦长约1/3处,流场的压力突跃脉动峰-峰幅值达到最大,高达15²0 kPa,导致较大的气动激振,叶片需承受较大的周期性气动负荷。     

低惯量涡轮转子结构设计与优化

论述了低惯量涡轮转子结构设计的特点和要求。在发动机载荷条件下,开展了带双辐板涡轮盘的低惯量涡轮转子结构设计研究。特别是针对双辐板涡轮盘结构及其连接结构的设计特点,进行了经验设计、结构拓扑优化和形状优化。对优化得到的两种双辐板涡轮盘结构形式进行了对比分析,并对焊接的双辐板涡轮盘结构的制造工艺进行了简要分析。结果表明,低惯量涡轮转子采用双辐板涡轮盘结构可行,能有效减轻涡轮盘质量,降低转子热惯性和机械惯性。     

航空发动机涡轮机匣温度试验对比验证研究

涡轮机匣结构复杂且工作环境比较恶劣,直接利用发动机部件开展机匣表面换热规律研究难度极大.通过采用简化模型的基础研究结合某发动机部件试验验证的方式进行研究.在基础研究中,取涡轮机匣的1个周期性扇段作为研究对象,对机匣结构中的一些圆弧、倒角、倒圆等结构进行了简化,采用数值计算和瞬态液晶测试技术获得了涡轮机匣表面换热经验关系式;在验证试验中,针对某发动机部件,在压力和温度均接近发动机工况下进行试验,获得了涡轮机匣表面换热情况,并对基础研究获得的经验关系式进行了验证.研究结果表明:基础研究获得的换热经验关系式在发动机部件试验中同样适用.应用的研究方法可供类似研究借鉴.     

航空发动机低压涡轮出口温度标定方法

在航空发动机试车过程中,针对数字电子控制器采集低压涡轮出口燃气温度(T6)高于试车台数采系统采集值的现象,进行了多轮测温试验,并结合T6测温原理、热电偶及补偿导线电气特性等,提出了从数字电子控制器电路板终端进行温度标定的方法,以确保在发动机实际试车过程中控制器测量的T6值更接近真实温度.试验结果表明:在航空发动机试车中采用在数字电子控制器T6采集电路板的补偿导线终端进行标定的方法后,由数字电子控制器与试车台数采系统采集的T6值相差1℃以内,证明该标定方法准确可行.     

某飞行科目中涡轮盘的损伤计算矢量喷管运动仿真

通过对某型航空发动机高压涡轮盘进行弹塑性有限元分析,计算涡轮盘在主次循环作用下的低循环疲劳寿命和寿命的概率分布,从而对涡轮盘在某飞行科目中的寿命损伤进行分析。对涡轮盘进行热分析;并对载荷谱进行分析处理,得出对涡轮盘损伤影响较大的主次循环和相应载荷谱;再对涡轮盘进行弹塑性分析,得到危险点处的应力、应变,计算涡轮盘确定性寿命和寿命的概率分布;利用线性损伤累积理论,得到涡轮盘在单次飞行和千小时飞行下的总损伤     

用于发动机涡轮盘叶片加工的夹具设计

介绍了用于加工发动机涡轮盘叶片夹具的设计准则,并给出了采用矢量三角函数和VC软件计算夹具极限偏差的公式及其判别依据,采用该准则设计的夹具用于涡轮盘叶片加工,产品满足设计要求,并通过了发动机热试车考核。     

Assessment of converting approach to efficient design of micro-turboprop engines

The design, manufacture and experiment of a shaft power unit for converting a micro-turbojet engine to a micro-turboprop in the class of less than 20 kW with the aim of obtaining maximum shaft power were described in this study. For this purpose, a Wren100 micro-turbojet engine was used as the gas generator, and the specifications of its outflow were measured. The optimal configuration of the inter-stage diffuser, which was an annular S-type diffuser, was selected based on its small total pressure drop and outlet flow uniformity. The power turbine was a single stage axial turbine that was designed based on the fixed nozzle angle assumption without any taper or twist in its stator. The turbine rotor was a bladed disk (Blisk) in which its unique blade profiles were designed based on the Wilson method. Subsequently, the shaft power unit was completed by designing and manufacturing an exhaust complex and gearbox. Finally, the micro-turboprop engine was tested with an overloading propeller. The results show a significant increase in the extracted power, an acceptable efficiency of the power turbine, and a significant reduction in the Specific Fuel Consumption (SFC) compared to other engines that use similar gas generators.