Statistical model for gas turbine engines exhaust emissions

A statistical analysis has been developed from the ICAO databank to predict aero-engines exhaust emissions during a landing and take-off cycle (LTO). The ICAO databank contains updated emission indices for a vast number of turbojet and turbofan engines only, with thrust ratings greater than 26.7 kN. Correlations are developed and proposed for turboprop and turboshaft engines to overcome the difficulty of assessing exhaust emissions from these engines in absence of industry data. LTO emissions are predicted for a turbofan-powered commuter airplane (Embraer E195) using the surrogate model. It is demonstrated that the predictions are closer to the values extracted from the flight data recorder than to the emissions calculated with the ICAO method. Thus, approximate emissions indices applied to actual flight procedures are a better choice than a standard ICAO LTO emission estimate from the databank. The correlations are then applied to the prediction of LTO emissions of a turboprop airplane (Bombardier Q400).     

Luster Polish Strengthening Treatment for Raceway Surface of Aeroengine Bearings

A new surface strengthening technology, luster polish strengthening treatment, was proposed to treat the raceway surface of aeroengine bearings (9Cr18Mo) with the centrifugal strengthening machine exclusively designed for luster polish strengthening treatment. The experimental results showed that luster polish strengthening treatment produced a compressive residual stress layer with a depth of over 80 μm below the surface of the bearing raceway, and thus effectively removed the metamorphic layer in the raceway surface. After luster polish strengthening treatment, the average surface hardness of the aeroengine bearing raceway was increased from 61.02 HRC to 63.01 HRC, the surface roughness was reduced from 0.06 μm to 0.03 μm, and the contact fatigue life of the aeroengine bearings was improved by about 90%, with the dispersion of fatigue life being reduced remarkably. Theoretical calculation result agrees with that obtained by experiment.     

指数分布在第二类Stirling数中的应用

采用概率的方法,把第二类Stirling数S（n,k）表示成服从指数分布的随机变量的矩,利用该表示得到了第二类Stirling数S（n,k）的一些特殊值,推导出了第二类Stirling数S（n,k）满足的递推关系式,并得到了新的递推关系式.     

CNG发动机阀座材料开发及其与气门匹配性试验

通过在强化型的基体材料中添加硬质颗粒和固体高温润滑剂,开发出了耐磨性高且具有自润滑性能的粉末冶金阀座材料。在用燃气加热的模拟试验机上进行对比试验,结果证明粉末冶金材料具有良好的综合性能。     

机车柴油机可变涡轮增压技术开发与应用

结合可变涡轮增压技术的特点,分析了可变涡轮增压技术对机车柴油机发展的影响,指出采用可变涡轮增压技术对改善机车柴油机部分负荷性能及对提高机车柴油机适应环境条件的能力方面具有很大的优势,最后介绍了可变涡轮增压技术在280系列机车柴油机上的开发与应用情况.     

机车和柴油机零部件变形及应力的计算机分析

本文用现代数值计算方法对机车和柴油机的主要零部件如曲轴、连杆、活塞、气缸盖、气缸套、机体、车体、转向架构架、辅等的变形和应力进行了分析,阐述了计算模型的建立、边界条件的处理和作用载荷的确定等,并对计算结果与实测作了对比。     

天然气发动机工作方式选择分析

比较了天然气发动机稀燃方式和理论空燃比方式下的排放情况、经济性能、动力性能、可靠性和耐久性。对改装汽车采用何种工作方式 ,提出了相应的建议     

基于基本竞争型网络的车用汽油机失火度的识别

针对汽油发动机失火度问题,提出了利用基本竞争型网络对失火度进行划分的解决办法,该方法利用排气中的HC、CO2或O2的浓度并结合基本竞争型网络自适应算法对所测信号值反复训练,最终得到样本空间的分类结果。     

基于粗糙集理论的柴油机燃油系统故障诊断研究

针对柴油机燃油系统的故障种类多的特点利用小波方法对燃油波形进行分析,提取时域及频域的故障特征参数,并使用粗糙集理论对这些故障特征参数进行约简,达到简化故障识别的神经网络的结构、加快辨识速度的目的.最后用RBF神经网络对所模拟的各类故障进行辨识,证实了粗糙集理论在柴油机燃油系统故障诊断中应用的可行性.     

应用激光显微摄影对柴油机喷雾粒度分布的测量研究

设计了以脉冲激光为光源的测定柴油机燃油喷雾粒度分布的显微摄影装置，并用该装置成功地测得了伞喷油嘴的燃油喷雾粒度场的时间特性和空间特性．研究结果为柴油机燃油系统和燃烧系统的设计与改进提供了可靠的依据．