诊断和修理航空继电器故障的优化系统

为了减少目前航空继电器用于发现和修理故障的费用 ,本文建立了基于规则、事实以及其自身经验的一个专家系统——适应性诊断系统 ADS( A daptive Diagnostic System) .该系统利用推理对航空继电器检测和替换顺序进行了优化 ,使节省的费用大约为 50 % .     

Temperature-induced phase separation in pseudoternary mixtures of Triton X-100–butanol–kerosene–water

The transparent Winsor IV domain in the phase diagram of the mixtures of emulsifier (Triton X-100 and butanol), oil (kerosene), and water is found to be 34% of the total phase diagram in presence of emulsifier with surfactant:cosurfactant::1:1, and is water dominant. Increase in cosurfactant/surfactant ratio inverts the Winsor IV domain to become oil rich. The plot of conductance of the microemulsions prepared by substituting water by brine against water content depicts the existence of three distinct phases like oil-in-water, bicontinuous, and water-in-oil microemulsion in the phase diagram. The phase contrast micrographs of the mixtures of different compositions in these three different phases reveal the existence of microdroplets of oil dispersed in water and water dispersed in oil. Further, the dynamic light scattering studies of these solutions reveal an inhomogeneity in the size distribution of the droplets. A temperature-induced clouding in the microemulsion domain leading to phase separation has been observed. Additives like glucose, sucrose, and sodium chloride decrease the cloud point (CP), while addition of ammonium thiocyanate increases it. A quantitative relationship of the clouding temperature with the composition of the microemulsion has been established. With increase in oil and emulsifier, the cloud point of the microemulsion increases. The separated phases after the clouding have been used for preconcentration of water-soluble metal ions as well as oil-soluble dyes. The turbid systems on heating led to separation into three isotropic phases which are found to be stable at ambient temperature. The stability of these phases is ascribed to the formation of stable microemulsions by mass transfer from one phase to other.     

Prediction of soot and thermal radiation in a model gas turbine combustor burning kerosene fuel spray at different swirl levels

Combustion of kerosene fuel spray has been numerically simulated in a laboratory scale combustor geometry to predict soot and the effects of thermal radiation at different swirl levels of primary air flow. The two-phase motion in the combustor is simulated using an Eulerian–Lagragian formulation considering the stochastic separated flow model. The Favre-averaged governing equations are solved for the gas phase with the turbulent quantities simulated by realisable k–? model. The injection of the fuel is considered through a pressure swirl atomiser and the combustion is simulated by a laminar flamelet model with detailed kinetics of kerosene combustion. Soot formation in the flame is predicted using an empirical model with the model parameters adjusted for kerosene fuel. Contributions of gas phase and soot towards thermal radiation have been considered to predict the incident heat flux on the combustor wall and fuel injector. Swirl in the primary flow significantly influences the flow and flame structures in the combustor. The stronger recirculation at high swirl draws more air into the flame region, reduces the flame length and peak flame temperature and also brings the soot laden zone closer to the inlet plane. As a result, the radiative heat flux on the peripheral wall decreases at high swirl and also shifts closer to the inlet plane. However, increased swirl increases the combustor wall temperature due to radial spreading of the flame. The high incident radiative heat flux and the high surface temperature make the fuel injector a critical item in the combustor. The injector peak temperature increases with the increase in swirl flow mainly because the flame is located closer to the inlet plane. On the other hand, a more uniform temperature distribution in the exhaust gas can be attained at the combustor exit at high swirl condition.     

Autoignition of surrogate fuels at elevated temperatures and pressures

Autoignition of Jet-A and mixtures of benzene, hexane, and decane in air has been studied using a heated shock tube at mean post-shock pressures of 8.5 ± 1 atm within the temperature range of 1000–1700 K with the objective of identifying surrogate fuels for aviation kerosene. The influence of each component on ignition delay time and on critical conditions required for strong ignition of the mixture has been deduced from experimental observations. Correlation equation for Jet-A ignition times has been derived from the measurements. It is found that within the scatter of experimental data dilution of n-decane with benzene and n-hexane leads to slight increase in ignition times at low temperatures and does not change critical temperatures required for direct initiation of detonations in comparison with pure n-decane/air mixtures. Ignition times in 20% hexane/80% decane (HD), 20% benzene/80% decane (BD) and 18.2% benzene/9.1% hexane/72.7% decane (BHD) mixtures at temperature range of T  1450–1750 K correlate well with induction time of Jet-A fuel suggesting that these mixtures could serve as surrogates for aviation kerosene. At the same time, HD, BD and BHD surrogate fuels demonstrate a stronger autoignition and peak velocities of reflected shock front in comparison with Jet-A and n-decane/air mixtures.     

基于GFM-VAR的我国通用航空产业演进阶段识别及政策强度有效性分析

为揭示通用航空产业系统演化的动态和有序规律,挖掘产业形成和可持续发展的阶段识别证据,针对产业演化数据的信息不完全和连续聚类特性,基于灰色系统理论和最优分割理论构建通用航空产业演进阶段识别的灰色生成序列最优分割模型(Grey sequence generation-Fisher Model,GFM),并运用VAR模型分析通航产业政策强度的有效性。首先运用灰色系统理论的(位置加权)几何平均强化缓冲算子(W)GASBO((Weight)Geometry average strengthening buffer operator)扩张演化数据波形特征并生成灰色序列矩阵;运用最优分割理论的组内离差平方和最小判断原则判定通用航空产业演化的有序递进阶段;然后,通过我国2004~2013年通用航空产业演进阶段的实证研究,发现:我国通用航空产业演化以2010年为分界点,先后经历了初创和成长两个阶段;基于VAR模型的脉冲响应函数确定我国通航产业政策强度受“倒逼出台”、“时滞限制”的影响呈弱有效性;基于政策强度(WGASBO算子)的灰色生成序列最优分割模型更有效、更具有可行性。     

Thermal behaviour of [Ca(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>](NO<Subscript>3</Subscript>)<Subscript>2</Subscript>

Motor gasoline must present characteristics that guarantee its quality and the good performance of internal combustion engines without harming the environment. The contamination of gasoline by solvents can seriously adulterate its physical-chemical properties and affect its volatility and detonation capacity. To investigate organic solvent adulteration in gasoline samples, thermal analysis technique (TG/DTG) can be used as an auxiliary tool in the study of the thermal behavior of liquid fuels, as demonstrated by the present work involving a comparative analysis of kerosene-free and doped gasoline.     

APX-RS相机在高速摄影中的应用

通过分析APX-RS数字化相机的性能特点及主要技术指标,设计了针对高速运动中高速段、中速段及低速段的运动物体飞行姿态拍摄的动态实验,得到了飞行物体清晰的拍摄图像和准确的运动速度。结果表明,该相机能较好地记录4Ma以内的高速运动物体的飞行过程。     

航空装备战斗损伤概率预测模型研究

装备战场抢修是保持和恢复装备战斗力的重要因素.预测并准确掌握航空装备的损伤概率,有利于作战指挥员和装备保障人员适时而准确的指导战场抢修任务的完成,以保证航空装备的持续作战能力.通过分析航空装备的战伤原因,运用概率分析法构建了航空装备战斗损伤概率预测模型,并提出了模型的改进建议.     

燃油燃料含硫化合物形态分布剖析技术研究进展

介绍了目前用于燃油、燃料(如汽油、柴油、煤油、喷气燃料)的硫化物形态分布剖析的多种分析技术,包括电化学方法和气相色谱与多种选择性检测器联用的方法(如GC - FPD、GC - AED、GC - SCD、GC - MS等),并对各种分析技术的研究现状进行了概述.     

毛细管气相色谱切割反吹技术归一化法定量分析航空煤油中的芳烃

用气相毛细管色谱切割反吹技术 ,和在FFAP毛细管预柱上芳烃比高它 3个碳数的烷烃之后出峰的特点 ,通过阀切换把芳烃反吹入非极性OV 1分析柱中 ,按照沸点进行分离。从预柱上先流出的组分和从分析柱上后流出的组分先后通过微型三通进入同一个FID检测器 ,因此可用校正响应因子归一化法进行定量分析。从预柱出口到检测器之间的阻尼柱阻力 6倍于分析柱阻力 ,反吹后因载气流速提高 5 .4倍而有效地压缩了谱带 ,提高芳烃等目标组分的检出灵敏度 2倍。通过切割反吹操作能很好地完成航空煤油中从苯到C11芳烃的检测 ,阀切换的可允许时间窗口达± 18s,且分析结果的重现性误差RSD≤ 4 .0 %。