共查询到20条相似文献,搜索用时 258 毫秒
1.
随着航空发动机的快速发展,其复杂性、综合化、智能化程度不断提高,对发动机安全性、可靠性的要求也不断提升,发动机健康管理技术应运而生,并在国产新研发动机上进行了运用。文中介绍了国内外发动机健康管理系统的发展现状,以及发动机健康管理系统的关键技术,从分层级规划、分阶段实施、分模块推进、分平台验证4个方面对发动机健康管理系统的发展提出对策建议。 相似文献
2.
为实现航空发动机状态等级的划分与识别、可靠性和剩余寿命的分析以及典型故障的诊断,基于灰靶决策理论、层次分析法和熵理论提出一种航空发动机健康监测方法。首先,以新航空发动机状态监测值作为靶心,用经层次分析法和熵理论综合算法优化权重系数后的灰靶模型计算靶心度;然后,结合故障严酷度和发生概率制定各健康状态等级的划分标准,并将靶心度转化为可靠度,在此基础上结合发动机性能退化曲线计算剩余寿命;最后,计算典型故障数据的靶心度作为参照实现故障类型的诊断。用某型航空发动机气路性能参数监测数据进行验证,结果表明笔者提出的算法可有效实现航空发动机健康监测,该算法具有较好的实用性和准确性。 相似文献
3.
航空发动机的健康安全状况对保证飞行安全有重要作用,如果不能对航空发动机的健康状况进行有效监控和管理,将直接危及飞行器运行安全,轻者会使飞机不能正常飞行,重者将会导致机毁人亡.所以,航空发动机健康安全管理对于保证飞行器的安全运行至关重要.本文所研发的航空发动机综合参数在线记录仪是航空发动机健康安全管理系统的硬件部分,针对... 相似文献
4.
5.
为采集、管理、处理并预测在翼航空发动机的性能参数,进而为航空发动机性能仿真和维修策略的制定提供支持,开发了航线数据处理系统,它是航空发动机全寿命周期管理系统的重要组成部分。该系统由航线信息管理、机队性能预测、自动报警和评估报告生成等4个功能模块构成。提出了基于多阶次多项式回归理论的机队性能趋势预示算法和基于改进层次分析法的发动机综合评估报警模型。中航集团国际航空公司的实际应用结果表明了上述模型和系统的正确性。 相似文献
6.
7.
8.
航空发动机弹性箔片气体动压轴承技术研究及性能评价综述 总被引:1,自引:0,他引:1
弹性箔片气体动压轴承广泛应用于航空发动机中,在减少航空发动机功率损失、提高发动机可靠性方面具有重要作用。综述了国内外箔片气动轴承的研究现状,介绍了航空发动机箔片气动轴承结构的发展和应用特点,重点讨论了箔片止推轴承的理论研究现状,比较了不同箔片气动轴承润滑建模方法、润滑求解方法、收敛控制方法,指出了弹性箔片气体动压轴承在航空发动机旋转机械中的巨大应用潜力,提出了气动轴承技术今后需要重点开展的研究发展方向,主要包括箔片动压气体轴承理论建模及其模型求解、箔片气动轴承的实验研究及试验台架的搭建测试、箔片动压气体轴承设计及加工制造、轴承表面涂层技术的研究以及箔片动压气体轴承技术的应用等。 相似文献
9.
10.
健康管理(PHM)技术是保障发动机安全性、可靠性的一项关键技术。本文首先阐述了发动机健康管理系统的重要性,结合当前发动机研制需要,分析了PHM系统需求。然后,结合OODA环思想提出了一种基于认知环的健康管理系统架构,根据机载系统和地面系统的特点设计不同的系统功能,并分别进行阐述。最后,总结了基于认知环的健康管理系统架构的优缺点和未来的发展趋势。 相似文献
11.
导电加热切削时刀具的热电磨损 总被引:1,自引:1,他引:0
导电加热切削时,由于强烈的电热效应,刀具磨损形态与传统切削加工方法有所不同。本文研究了导电加热切削的电热特性和电物理现象,分析了导电加热切削时刀具的热电磨损及其机理。 相似文献
12.
An analysis of the effects of lens aberrations on the phase contrast images used for strain measurement by geometric phase analysis (GPA) in the TEM shows that errors may result when strain gradients are present and when [formula: see text] at the reciprocal lattice spacing used for the analysis. This conclusion is demonstrated experimentally using a model specimen consisting of a strained Si layer grown epitaxially on a Si-Ge alloy substrate. Image simulations for this model specimen show that strain gradients can introduce oscillations in strain maps when the defocus is not optimized for GPA. This work also makes it possible to identify other potential sources of error in GPA. 相似文献
13.
Wenji Xu Xin Liu Jing Sun Lin Zhang 《The International Journal of Advanced Manufacturing Technology》2013,66(1-4):407-415
Electric hot machining (EHM) can improve cutting performance through heating resistance, which softens the material in the deformation zone. In this study, an empirical formula for heating resistance is presented, and its variance with the orthogonal regression experiments is analyzed. The results show that heating resistance increases with cutting speed and heat current but decreases as feed rate and cutting depth increase. Feed rate has the greatest influence on heating resistance. Furthermore, an empirical formula with finite element simulation (FES) is constructed to describe the temperature increase triggered by Joule heating of the heating resistance. Both three-dimensional (3D) FES and experimental verification of the cutting force and the temperature field during the EHM process are conducted, combined with a 3D cutting model and an Umbrello constitutive relation. The results show that a lower cutting force can be achieved when the heating current is greater than or equal to 160 A. The chip in the deformation zone has the highest temperature, and the optimal heating current for optimal cutting temperature is 168 to 190 A. 相似文献
14.
本文根据传统导电加热切削生产效率低,且易烧蚀刀具等问题,提出通过断屑器导电块引入电流进行电加热切削。理论分析及实验结果表明,对于切屑里带状的难加工材料,断屑器导电加热切削能够克服传统电加热切削存在的问题,是一种有效的新加工方法。 相似文献
15.
利用导电加热切削抑制积屑瘤和鳞刺的研究 总被引:1,自引:0,他引:1
通过导电加热的温度补偿,导电加热切削能有效抑制金属切削表面的积屑瘤和鳞刺。刀-工接触区的温升与加热电流密切相关,存在一个与最佳切削温度相适应的最佳加热电流值范围。 相似文献
16.
A. G. Stamatis 《Journal of Mechanical Science and Technology》2011,25(2):469-477
In the present paper, limitations concerning three implementations of gas path analysis (GPA) methods are investigated and
their diagnostic effectiveness is evaluated. The methods were tested for different sets of faults on a twin shaft gas turbine
with an instrumentation set typical of today’s engines. Test results revealed that classical GPA is not sufficient. Correct
diagnosis is provided only when one already knows a subset of components containing the fault; otherwise, the fault may be
attributed to other component (s). The effectiveness of a second method that implements Multi Operating Point Analysis (MOPA)
is related with the assumption of non varying health parameters with deviations along with the operating point. Cases of wrong
diagnosis were detected when the above assumption was violated. Improvement on the diagnostic effectiveness of the MOPA method
has been verified through careful selection of the parameters defining the operating point. Further improvement on diagnostic
ability was achieved when a third, recently proposed method was applied. The method uses information produced from existing
sensors when artificial operating points are defined close to the initial operating point. It was found that the third method
can detect and correctly identify faults even in cases where the multipoint method fails. 相似文献
17.
自陈式问卷调查不可避免地受到社会称许性效应的影响。国内广泛开展的大学生学情调查对社会称许性问题关注不够。本文利用国内某“985”院校C大学参加2013年度“中国大学生学习与发展追踪研究”(CCSS)调查获得的数据,揭示了社会称许性与学情调查核心指标的正相关关系及其反应效应的客观存在。并且通过分析社会称许性与学生自我报告的学业成绩、真实GPA之间的关系,证实了社会称许性对学情调查数据的切实影响。为此,学情调查应对社会称许性予以必要的关注和重视,加强研究,并特别关注偏低的社会称许性反应。 相似文献
18.
Local rotations due to mixed‐type misfit dislocation at α‐Fe2O3/α‐Al2O3 heterostructure interface 下载免费PDF全文
The misfit dislocations at α‐Fe2O3/α‐Al2O3 heterostructure interfaces were investigated by high‐resolution transmission electron microscopy (HRTEM), geometric phase analysis (GPA) and dislocation density tensor analysis. When imaged along the [110] direction, the misfit dislocation core is a mixed‐type, which can be characterised by one extra (102) plane and one extra (104) plane of α‐Al2O3. Dislocation density tensor analysis gave a very high accuracy in determining the corresponding Burgers vectors of two extra half‐planes. By comparing the measured Burgers vectors with theoretical ones, we are able to determine local rotations in the dislocation core region: the (102) plane is rotated clockwise 6.25° and the (104) plane is rotated anticlockwise 4.81°. Such a local rotation is favourable from the viewpoint of both energy and function to relax lattice misfit. 相似文献
19.
20.
从多刚体仿真分析、刚柔耦合仿真分析、机液耦合仿真分析三种角度提出了机液耦合机构的比较完整的仿真分析的实现策略,最后提出了仿真分析中应当注意的问题。 相似文献