一种平尾涡流发生器设计和流动控制研究

在飞机表面安装涡流发生器,可以起到改善当地流态的作用,达到减阻、增升、降噪、减小旋流畸变的目的,而平尾的气动特性直接影响飞机的飞行安全。基于改善飞机平尾在负迎角下流动特性的应用需求,设计一种安装于平尾下表面的涡流发生器。通过数值模拟方法研究平尾在不安装涡流发生器和安装涡流发生器两种构型下的流动特征和机理,分析飞机在负迎角下的俯仰力矩特性。结果表明：安装涡流发生器的平尾负失速迎角推迟了4°,负迎角下的俯仰力矩拐点推迟了4°左右,拓宽了飞机的飞行边界。     

基于AI+神经网络的数字化故障电弧识别方案研究

线路故障电弧的特征随着电力电子技术的提高更趋复杂，传统的故障电弧识别方式已无法应对新型用电系统。对比传统故障电弧识别方案，研究故障电弧产生类型和新型检测技术，提出基于谐波因素、总谐波畸变率、电流零休时间、电流变化速率、电流周期性等典型时域、频域特征的AI+神经网络的数字化故障电弧识别方案。该方案运用回归算法向量机对特征图进行分类处理，通过正向传输运算、反向传输运算和迭代回归运算三个步骤执行卷积神经网络，频繁迭代回归以获得最佳特征识别图。本文以调光器的故障电弧识别为例，对故障识别方案进行验证，结果表明采用此方案可实现更高效、更精准、更稳定地识别故障电弧。     

抽油机故障诊断的分布驱动主动学习算法

抽油机示功图直观显示了抽油机工作情况，但实际工况情况呈现典型的长尾分布特性，类别严重不平衡。传统方法无法准确识别小类别工况，也无法获得井下工作状态准确识别。针对这一问题，提出一种基于分布驱动的多类别长尾数据代价敏感主动学习算法（Cost-sensitive active learning algorithm based on distribution -driven multi-class long-tailed data， CALA）。首先，考虑数据分布特性，以最小化代价为优化目标确定数据的最佳聚类簇数；其次，通过加入预分类误差代价来更新之前得到的最佳聚类簇数；然后，构建集成分类模型作为分类器；最后，通过迭代来平衡数据分布。采用某油田真实的示功图数据进行测试，显著性实验分析证明CALA在小类别工况诊断上具有更好的性能。     

多绕组双流发电机励磁调压系统建模与Saber仿真

双流发电机励磁调压系统对发电机交直流电源的输出具有重要作用。文章主要分析了励磁调压系统的组成及工作原理,系统分别采用交/直流调压器(WZT-3型/SLT型),实现飞机发动机起动所需 115/200V、400Hz交流电和 28/56 V、0～70 V直流电的输出。采用 Saber建立仿真模型,仿真结果验证了励磁调压系统的可行性。     

Influence of sub boundary layer vortex generator height and attack angle on cross-flows in the hub region of compressors

It has been recently shown that Sub Boundary layer Vortex Generator (SBVG, abbreviated as VG hereafter) can suppress the Cross-Flow (CF), and therefore, can eliminate corner separation and increase aerodynamic loading when installed on the end wall inside middle-load compressor passages. However, when VGs are applied in high-load compressors, it is difficult to achieve ideal results. This is because the definition of the VG attack angle in the presence of CF in existing research is confusing, and the stronger CF in high-load compressors worsens the problem and results in an improper design and optimization range of VG attack angle. Therefore, this paper clarifies the definition of the VG attack angle in the presence of CF and reveals the CF controlling mechanism of VG on a flat plate. The differences in the flow phenomena around a VG both with and without CF are also studied. The numerical results show that a larger height or attack angle of the VG generates a greater CF suppression effect. However, the cross velocity increases when surmounting the primary vortex induced by the VG, except that this enhanced CF is less conspicuous for larger VG heights. Compared to the cases without CF, the VG suffers an additional loss because of the stronger separation and primary vortex loss caused by the CF.     

变推力液体火箭发动机推力调节技术研究综述及发展趋势

系统梳理了国内外变推力液体火箭发动机调节控制技术的研究历程及研究现状，并结合我国航天动力研究基础，指出通过在主系统或副系统管路上设置液体或燃气流量调节装置、通过可调结构的针栓式喷注器同步对流量与压力进行匹配调节仍然是实现大范围变推力调节的两种主要手段；分析了变推力液体火箭发动机推力调节的关键技术及其解决途径，预测了未来一段时期内变推力液体火箭发动机及其调节技术发展趋势，提出了若干适合我国国情的研究建议，为我国低成本、可重复使用天地往返运输技术的发展和有关研究者开展研究工作提供一定的参考。     

往复节流式正脉冲发生器性能分析CSCD

在石油开采与钻探领域,脉冲发生器作为旋转导向系统井下信号传输系统的重要组成部分,提高压力脉冲幅值有助于提升旋转导向系列产品的市场竞争力。为了揭示其工作原理及提高压力脉冲幅值,基于计算流体动力学,利用用户自定义函数(UDF)、动网格技术、非牛顿流体模型,借助Fluent平台对往复节流式正脉冲发生器进行了动态数值实验。利用离散形式的动量方程将主阀体与电磁阀的被动运动转变为主动运动,选择适用于k-ε湍流模型的赫-巴非牛顿流体本构方程描述泥浆,提高了计算的收敛性与运动的可控性。基于非牛顿流体的流固耦合方法,更真实地模拟了脉冲器在井下工作过程。结果表明限流环内径越小或入口排量越大,则压力脉冲幅值与信号发生频率越大。     

Integration of Landsat-8 and Sentinel-1 dataset to extract geological lineaments in complex formations of Tepal mountain area,Shahrood, north Iran

Recently, the detection and extraction of geological lineaments have become an essential analytical technique to find relationships between the characteristics and occurrence of hydrogeology, and tectonic studies. The use of remote sensing, with the progressive development of image enhancement techniques, provides an opportunity to produce more reliable and comprehensive lineament maps. In this paper, semi-automatic approach based on Landsat 8 and Sentinel 1 radar data is proposed for lineaments extraction and validation. The combined method of linear filtering and automatic line module ensures a high degree of accuracy resulting in a lineament map. Based on identified lineaments, Sentinel1 is more capable of detecting edges than Landsat8, but the primary orientation lineaments extracted from Landsat8 and Sentinel1 were different. So, by combining band6 of Landsat8, and VV and VH polarization of Sentinel1, the area lineaments were extracted with high accuracy. Rose diagram showed the extracted lineaments' orientation is in good compliance with the region's existing faults. Also, the formations' lineament length density has good consistent with the density of the faults in the geological map.     

动态负调约束下固体冲压发动机燃气流量控制算法研究

变流量固体冲压发动机工作过程中，常采用控制燃气发生器压强的方式调节燃气生成量，在跟踪变化压强指令过程中，流量会产生明显的负调现象，严重影响发动机系统的安全性和可靠性。为 解决这一问题，本文以具有高度非线性、强时变特性的燃气发生器系统为对象，构建了基于粒子群算法的流量调节自适应PI控制器，并给出一种利用自适应微分跟踪器对期望控制指令进行“整形”的负调改善算法；首先，结合负调发生、终止判据，综合考量系统流量安全裕度，负调发生方向，构建了适配于动态负调约束的自适应跟踪微分器（TD），克服了传统跟踪微分器在负调抑制过程中控制精度不高，指向性不强等缺陷；进一步，开展了多工况下的负调抑制算法仿真校验，结果表明：所设计自适应控制算法具备良好的燃气流量控制能力，可实现在基本不改变响应时间情况下，将最大负调量削减56.6%的控制效果，展现出良好的工程应用前景。     

Design and analysis of a novel hybrid cooling method of high-speed high-power permanent magnet assisted synchronous reluctance starter/generator in aviation applications

To improve the heat dissipation performance, this paper proposes a novel hybrid cooling method for high-speed high-power Permanent Magnet assisted Synchronous Reluctance Starter/Generator (PMaSynR S/G) in aerospace applications. The hybrid cooling structure with oil circulation in the housing, oil spray at winding ends and rotor end surface is firstly proposed for the PMaSynR S/G. Then the accurate loss calculation of the PMaSynR S/G is proposed, which includes air gap friction loss under oil spray cooling, copper loss, stator and rotor core loss, permanent magnet eddy current loss and bearing loss. The parameter sensitivity analysis of the hybrid cooling structure is proposed, while the equivalent thermal network model of the PMaSynR S/G is established considering the uneven spraying at the winding ends. Finally, the effectiveness of the proposed hybrid cooling method is demonstrated on a 40 kW/24000 r/min PMaSynR S/G experimental platform.