航空发动机试车台推力测量中的温度影响

航空发动机在试车过程中,推力测量精度会受到温度、湿度、压力、振动、电磁场等因素的影响。其中,温度对推力测量的影响较大,会导致传感器测力不准、试车台架形变等问题。本文设计了多种工况下的推力测量试验,分析温度因素对试车台推力测量精度的影响。由结果可知,采用传感器双向预紧的高精测量组件和传感器保温形式,对试车台测力精度的提高有显著作用。     

发动机关键参数测量与状态监测系统

系统地阐述了航空发动机试验关键参数测量与状态监视系统.该系统包括转速测量通道2个、燃油流量测量通道2个、压力测量通道8个,基于PCI总线,在工控机上运行,由相应的系统软件实现参数测量与状态监视.软硬件设计中充分考虑了测量通道的可扩展性,实现了测量通道的自动扩展.     

车用发动机活塞稳定工况温度测量

采用温度记忆螺钉法对桑塔纳汽车发动机活塞顶部与裙部温度进行了测定,分析了测试结果,并与有限元计算所得结果进行了比较。该法测活塞温度无需引线及专用设备,简便易行、成本较低,具有实用性。     

航空发动机设计制造协同流程及关键技术研究

结合中国航空发动机行业多厂所联合研制的现状和特点,研究了航空发动机设计制造协同工作业务流程,分析了设计数据的预发放和工艺会签、设计数据正式发放和工程更改等协同工作流程,重点研究探讨了设计-制造协同工作方式、业务流程建模、流程控制、并行团队组织与管理以及信息共享与集成等关键技术。     

航空发动机设计制造协同流程及关键技术研究

结合中国航空发动机行业多厂所联合研制的现状和特点,研究了航空发动机设计制造协同工作业务流程,分析了设计数据的预发放和工艺会签、设计数据正式发放和工程更改等协同工作流程,重点研究探讨了设计-制造协同工作方式、业务流程建模、流程控制、并行团队组织与管理以及信息共享与集成等关键技术.     

曲线拟合在航空发动机内壁温度测试中的应用

借助螺塞热电偶温度传感器和多路数据采集卡,建立了瞬态温度测试系统,提出利用曲线拟合外推法来实现对发动机内壁瞬态温度的测量.在此基础上,利用氢氧焰模拟航空发动机内部瞬态高温源,分别得出了传感器和红外测温仪测得的发动机内壁表面温度变化曲线.实验结果表明:2条结果曲线的整体变化趋势,特别是在峰值处具有较好的一致性,且其精度达到1.84％,从实验上验证了该方法的可行性.     

自动测量与信息化技术在航空发动机燃油总管试验中的应用

随着计算机和自动测量技术的发展,测量仪器和计算机的关系日益密切.目前伴随着计算机技术的发展,在软硬件方面积累了大量经验,创造了丰富的资源.计算机技术的很多成果很快应用到测量和仪器领域.利用PC极其丰富的软件和硬件资源,可以大大提高测量系统的功能,许多方便实用的自动测试系统随之而产生.与计算机相结合已经成为测量仪器和自动测量系统发展的必然趋势.     

红外辐射吸收法测量航空发动机燃气温度

航空发动机加力燃烧室出口温度较高,采用红外辐射吸收测量可以克服传统热电偶测量的缺点.利用红外光谱的某一强辐射吸收谱带的特点,设计了一套红外测温仪光学系统,并给出了具体的试验措施和信号采集与处理方法.     

石油生产测井多参数测量及温度线性化补偿

介绍了一种温度和压力补偿方法，并将多个信号通过一根电缆进行传输     

航空发动机连杆裂解工艺研究

介绍航空发动机连杆的特点与裂解加工的质量要求,在此基础上分析连杆材料与热处理对裂解加工的影响;对20CrMoA渗碳淬火连杆进行裂解加工试验,确定材料的热处理方法;分析工艺孔对加工质量的影响,给出合理的裂解工艺孔数量与形式;确定初始裂纹槽槽深、张角和曲率半径的取值范围;最后介绍同步浮动裂解装置,并提出"浮动定行程"裂解工艺加工方法,使裂解加工质量得到提高,获得优良的断裂面,解决了航空发动机连杆对裂解加工要求高的工艺难题.     

Uncertainty analysis and ANOVA for the measurement reliability estimation of altitude engine test

The altitude engine test is carried out to measure the performance of the engine of flight vehicle at the high altitude environment prior to the flight test. During the test, The measured pressures and temperatures at various positions, air flow rate, fuel flow rate, thrust of the engine are measured. These measured values are used to calculate the representative performance values such as the net thrust and the specific fuel consumption. Hence each of the measured parameter has effects on the total uncertainly of the performance values. In this paper, the combined standard uncertainties of the net thrust and the specific fuel consumption were estimated from the uncertainties of the various measured values. Also, by estimating the repeatability and the reproducibility, the confidence levels of the altitude engine test were validated by the analysis of variation on the repeated test data by different tester groups.     

进气畸变对发动机压缩系统稳定性影响的数值模拟

介绍了一种在发动机环境下评定航空燃气涡轮发动机压缩系统稳定工作边界的数学物理模型。研究了进气畸变对航空燃气涡轮发动机压缩系统稳定工作边界的影响。对总压畸变进气条件下压气机稳定工作边界的变化进行了计算分析,结果表明进气总压畸变对发动机稳定性有很大的影响,使得压气机稳定工作边界在压气机的特性图中向右下方移动,降低了发动机的喘振裕度。主要数学物理模型可以正确地反映发动机压缩系统的工作状况,用它判断发动机不稳定工作点的重复性和灵敏度都比较好。     

基于一体化探针的航空发动机内流 多方向压力测量技术研究

航空发动机内流场多方向压力测量可为航空发动机压缩比计算提供重要的数据支撑。本文针对现有多孔探针结合电类压力测量法存在迟滞且测量精度低的问题;结合多孔探针和光纤传感技术优势,设计了一种适用于航空发动机内流多方向压力测试的一体化探针。分析了一体化探针的多方向压力传导与压力测量原理,采用FLUENT软件对多方向气流传导性能进行分析并优化多孔气流传导结构参数;研制了5孔一体化光纤探针并开展了压力测试实验。结果表明:在0.7～1.6 MPa压力范围内,一体化探针各方向压力传感器的平均灵敏度为-16.267μm/MPa,重复性误差小于2.98%,各传感器压力测量最大误差小于1.72%。     

渗金属气压对光电高温计测温精度影响的实验研究

为准确控制双辉等离子渗金属工件的温度,借助自制的一套热电偶测温实验装置,对光电高温计测温进行了比对实验,探讨了气压对光电高温计测温精度的影响。实验结果表明:在双辉等离子渗金属过程中,对同一工件温度,随工作气压的升高,光电高温计所用的ε值也增大。工作气压每增高5～10Pa,将ε值提高0 1,这时光电高温计的温度测量误差会小于±3℃。     

Wind pressure transients in the tunnel inside a station caused by a passing high speed train

When a High Speed Train (HST) passes through a station with no stop, effects of wind pressure transients caused by this passing train have to be considered for the safety of passengers on the platform and for the possible structural safety problems as well. In Gwangmyeong and Daejeon stations of the Korean high speed railroad, tunnels inside stations for the passing train are proposed to reduce the noise and wind pressure transients to the passengers on the platform. In the present study, transient 3-D full Navier-Stokes solutions with moving mesh to implement train movement are obtained and compared with the results obtained by the towing tank experiment. Investigations on flow phenomena for various train speeds and design modifications are also performed.     

齿轮参数CCD自动测量系统的研究

提出一种齿轮参数CCD自动测量的方法,给出测量步骤,构造测量硬件系统,并用VC++语言编写了系统软件。通过测量实例证明,所研制的自动测量系统达到了预期的效果。     

超燃发动机流场组分浓度的在线测量

为了正确评价超燃发动机试验状态,采用自发拉曼散射技术在线测量了超燃发动机流场的主要组分。基于发动机试验条件和发动机与光学诊断技术的接口,建立了用于发动机流场组分测量的自发拉曼散射实验系统;测量了多车次发动机试验过程中流场主要组分的拉曼光谱;最后,通过光谱计算获得了流场主要组分浓度信息并重点分析了来流氧气含量及其变化情况。实验显示:发动机试验中,部分车次试验补氧后的来流中氧气的最大含量达到了30%,最小含量为18%,说明发动机试验过程中,对补氧量的控制精确和稳定性还有待提高。结果表明:采用自发拉曼散射技术可以较好地完成来流主要组分浓度测量工作,测量结果可用于发动机试验数据的分析及来流补氧控制方式和控制精度的改进。     

Development of a device for the measurement of thermal and fluid flow properties of heat exchanger materials

As yet, no standard equipment exists for the measurement of heat transfer through porous materials, such as metal foams (metals with a high volume fraction of porosity). Most research in this area has been carried out using bespoke test rigs. Here the creation of a test rig specifically developed for the measurement of the heat transfer of metal foams is reported. This method has been applied to laboratory made samples processed by replication and examples of commercially available aluminium foams (Duocel and Corevo), and should be suitable for the testing of all materials with comparable permeability. As this equipment is new and unique, the design will be discussed in detail, along with the various tests that were performed to ensure reliability and consistency with other methods and published data.     

The temperature, pressure and time dependence of lubricant viscosity

The general form of the pressure (Proc. Am. Acad. Arts Sci. 77 (1949) 117) and temperature (Physical properties of molecular crystals, liquids and glasses (1968) 350) dependence of viscosity has been known for at least 50 years. Viscosity varies with temperature in a greater than exponential manner and temperature–viscosity equations generally allow for an unbounded viscosity at some characteristic temperature. At high-pressures the pressure–viscosity response is likewise greater than exponential, often following a less than exponential response at low-pressures. In spite of this known behavior, tribologists working in EHL have generally assumed less than exponential pressure response as a means of applying the Eyring stress aided thermal activation theory to the viscous regime of EHL traction. As justification, time dependence of the lubricant properties in the response to a pressure transient has been advanced. We present acoustic, capillary and impact measurements for timescales less than EHL. While time dependence of properties may be important in the viscoelastic regime of traction, this paper will show that for the timescale of viscous response, a significant time dependence of viscosity is unlikely.