随形固定自适应夹具加工变形控制方法

叶片的加工精度及其稳定性对航空发动机的性能有直接的影响,由于叶片的薄壁和曲率多变特点,易受装夹、切削力和残余应力的影响而产生弯曲、扭转变形。针对该问题,本文提出了一种随形固定自适应夹具加工变形控制方法,可以将叶片无应力装夹,并将加工过程中产生的变形逐层消除。实验结果表明,采用随性固定自适应夹具加工变形控制方法,可以有效控制叶片加工过程中产生的变形,提高加工精度。     

Tech-X发动机及其先进技术分析

Tech-X发动机是GE公司研发的用于超大航程公务机的新一代高涵道比涡扇发动机.本文就Tech-X发动机的性能指标和先进技术创新进行了概括性分析,供相关人士参考.     

高压液氧供应系统管路设计

高压液氧供应系统是我国压力最高的挤压式液体火箭发动机试验台的关键分系统。在系统设计过程中，通过合理布置管路，设计专用固定支架，采用自然补偿和堆积绝热技术，解决了高压低温推进剂系统管路设计中的难题。该系统顺利通过气密性检查和调试，经多次热试车考核，系统稳定可靠，满足设计要求。     

INTERNET网检工具逻辑算符及检索表达式优化

对ＩＮＴＥＲＮＥＴ网检工具逻辑算符进行分析和比较。在此基础上，提出制定和优化检索表达式的方法。     

Design for aircraft engine multi-objective controllers with switching characteristics

The aircraft engine multi-loop control system is described and the switching control theory is introduced to solve the regulating and protecting control problems in this paper. The aircraft engine multi-loop control system is firstly described and the control problems are formulated. Secondly, the theory of the smooth switching control is devoted and a new extended scheme for the smooth switching of a switched control system is introduced. Then, for the key technologies of aero-engines switching control, a design algorithm is presented which can determine which candidate controller should be put in feedback with the plant to achieve a desired performance and the procedure to design the aircraft engine multi-loop control system is detailed. The switching performance objectives and the switching scheme are given and a family of PID controllers and compensators is designed. The simulation shows that using the switching control design method can not only improve the dynamic performance of the aircraft engine control system and reduce the switching times, but also guarantee the stability in some peculiar occasions.     

NOx emissions of turbofan powered unmanned aerial vehicle for complete flight cycle

Unmanned Aerial Vehicles (UAVs) have been getting more and more popular in both civil and military arena. Similar to manned aircraft, their propulsion systems or engines emit harmful gases such as nitrogen oxides. Since UAVs have different mission profiles and operational parameters than manned aircraft, it is worthy to investigate their NO_x emissions. Therefore, in this study, NO_x emissions of a turbofan powered UAV for complete flight cycle was calculated and optimized within a range of altitude and speed parameters. NO_x emissions were calculated based on ICAO ground test data and corrected to any speed and altitude during flight legs using both Boeing Fuel Flow Method 2 and DLR Fuel Flow Method. Total NO_x emissions were calculated for complete flight cycles for different altitude and speed parameters. Numerical results were presented graphically and additionally optimization studies were conducted. Optimization studies include determination and comparison of speed and altitude for minimum NO_x emissions by the two fuel flow methods and maximum loiter time achievable by UAV.     

变循环压缩系统涵道流动计算模型及模式转换倒流判据研究

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，本文提出的倒流判别准则具有较高的可靠性和可行性。     

浅谈机队发动机换发计划管理

航空公司机队发动机换发计划管理是发动机工程管理的有机组成部分，换发计划管理需要细致考量影响的因素，并结合实际进行优化调整。     

基于功率裕度的某型发动机全寿命性能研究

随着使用时间不断增加,研究飞行队所有选装ARRIEL2S系列发动机全寿命性能变化趋势的必要性突显.针对SRRIEL2S系列发动机全寿命性能参数变化特点,提出使用基于可几误差舍弃理论处理发动机功率校验数据,分区间描绘该系发动机全寿命性能指标变化趋势,给出该系发动机全寿命性能特点,为机务工程人员监控该系发动机提供有利依据；提出延长功率校验间隔的假设,并在理论上做了充分论证,为节约该系发动机运行成本提供一个明确及可行的方向.