大力值精密机械力源的研制

运用"平面二次包络弧面蜗杆传动"技术,研制出一种"轴向可调隙蜗轮蜗杆传动付",将它应用到力源动力传动的伺服减速机构中,驱动精密滚珠丝杠上的动横梁来完成对参考力传感器的粗加载。运用物理学中的"逆压电效应"原理,采用压电陶瓷材料和专门的工艺方法制作的力传感器微变形补偿装置——压电陶瓷力调节器,并将它应用到力源的精加载闭环控制中,实现了大载荷下参考力传感器微小力值变化的精确控制,研制出的大力值精密机械力源最大负荷为3 MN。     

我国航天测控通信系统配置CCSDS SLE业务方案设计

介绍了CCSDS SL正业务的具体内容,提出了在我国航天测控系统中采用CCSDS标准的SLE传输协议实现国际联网的设想,并给出了前向遥控SLE业务的配置方案。     

热斑对涡轮级转静干涉噪声影响数值研究

利用结合相位延迟方法的求解器,对进口有热斑存在的某高压涡轮级流场进行三维非定常计算,然后利用模态匹配方法在涡轮转子下游管道中提取出转静干涉离散噪声信息.通过与进口无热斑存在算例比较表明:在一倍叶片通过频率下,向下游传播的转静干涉离散噪声总声功率级增加了约5.9dB;在二倍叶片通过频率下增加了约11.6dB.      

五自由度位移平台控制系统设计

介绍了一种五自由度位移平台控制系统的设计。该系统为风洞流场中温度、压力等传感器进行测试提供位移平台。采用自行设计的运动控制器,结构简单,控制精确;移植了嵌入式实时操作系统μC／OS-Ⅱ,通过μC／OS-Ⅱ来调度运动控制器的多个任务;采用PC机作为上位机,为用户提供友好的人机界面。     

一种工业热电阻检定系统的设计

为实现对工业热电阻的自动检定,提高检定工作效率及量值传递的准确性,设计了一种工业热电阻自动检定系统。根据热电阻检定工作原理和实现自动检定的思想,论述了系统的硬件结构组成和检定系统操作步骤。系统采用测温电桥与低电势扫描开关配合,在工业三线铂电阻的检定中,可以实现二线接法和三线接法的自动转换。系统操作软件以VB作为开发平台,实现自动控温、采集数据和输出word报表等。实际使用表明,系统设计结构合理,软件操作方便,量值传递准确可靠。     

Numerical Investigation of Flow Separation Control on a Highly Loaded Compressor Cascade by Plasma Aerodynamic Actuation

To discover the characteristic of separated flows and mechanism of plasma flow control on a highly loaded compressor cascade, numerical investigation is conducted. The simulation method is validated by oil flow visualization and pressure distribution. The loss coefficients, streamline patterns, and topology structure as well as vortex structure are analyzed. Results show that the numbers of singular points increase and three pairs of additional singular points of topology structure on solid surface generate with the increase of angle of attack, and the total pressure loss increases greatly. There are several principal vortices inside the cascade passage. The pressure side leg of horse-shoe vortex coexists within a specific region together with passage vortex, but finally merges into the latter. Corner vortex exists independently and does not evolve from the suction side leg of horse-shoe vortex. One pair of radial coupling-vortex exists near blade trailing edge and becomes the main part of backflow on the suction surface. Passage vortex interacts with the concentrated shedding vortex and they evolve into a large-scale vortex rotating in the direction opposite to passage vortex. The singular points and separation lines represent the basic separation feature of cascade passage. Plasma actuation has better effect at low freestream velocity, and the relative reductions of pitch-averaged total pressure loss coefficient with different actuation layouts of five and two pairs of electrodes are up to 30.8% and 26.7% while the angle of attack is 2°. Plasma actuation changes the local topology structure, but does not change the number relation of singular points. One pair of additional singular point of topology structure generates with plasma actuation and one more reattachment line appears, both of which break the separation line on the suction surface.     

螺栓联接结构振动特性有限元分析方法的研究

复杂的联接结构是由多个子结构组合而成,从而形成接触面。研究表明,其接触刚度显著影响系统的动力学特性。以螺栓联接结构的“L”形实验件为例,利用有限元软件建立了系统的粘结结合面模型和罚函数法接触模型,获得了系统固有频率以及振型,对比实验结果,分析了不同建模方式对系统振动特性的影响。     

高速巡航导弹翼面结构热-振联合试验研究

由于高速巡航导弹飞行速度快、滞空时间长,在气动加热引起弹翼、整流罩和弹体等部件外表面温度升高的同时,还会伴随长时间的剧烈振动。气动加热产生的热环境会使材料和结构的弹性模量、刚度等力学性能发生明显变化,复杂的机动飞行过程又会使结构中出现较大的温度梯度,引起热应力场的改变,进而对导弹结构的固有振动特性带来严重的影响。以高速巡航导弹翼面结构为研究对象,进行了热环境下的翼面结构热-振联合试验,获得了不同温度条件下翼面结构固有频率等振动特性的变化规律,为巡航导弹弹翼结构在高速、热振动环境下的安全设计提供了可靠依据。     

Study of mid-latitude ionospheric convection during quiet and disturbed periods using the SuperDARN Hokkaido radar

Westward ionospheric convective flows around midnight are frequently observed at mid-latitudes. They can be generated by so-called disturbance dynamo mechanisms working mainly in the mid-latitudes. To understand the influence of disturbance dynamo effects in the mid-latitudes, we studied the latitudinal distribution of westward flows in association with several kinds of geomagnetic disturbances using the SuperDARN Hokkaido radar. This radar creates high temporal resolution (1 s to 2 min), two-dimensional observations measuring the line-of-sight velocities of ionospheric plasma irregularities, which can be regarded as line-of-sight velocities of ionospheric convection in the mid-latitude region from 40° to 50°. This region could not be monitored using preexisting SuperDARN radars. In this study, we used ionospheric echo data obtained by the SuperDARN Hokkaido radar over 5 years (December 2006 to November 2011). We identified westward flows around midnight at about 40° to 55° geomagnetic latitude. Additionally, the data showed that the westward flow around midnight intensified under high geomagnetic activity (high Kp). This suggests that the disturbance dynamo could affect the mid-latitude ionospheric convection. We performed Superposed Epoch Analysis (SEA) to study the influences from the geomagnetic disturbances on mid-latitude ionospheric convection. We found no obvious influence during major storms (minimum Dst below −60 nT). SEA was also used to study the temporal and latitudinal dependence on the influences from substorms. From analysis of 36 events of AL-defined substorms, we saw that the influence of substorms lasted from 5 to 20 h after the onset between 44° and 53° geomagnetic latitude. The westward flow at mid-latitude grew to a maximum at 12 h after the geomagnetic substorm onset. This is consistent with the results of past numerical simulation studies of the disturbance dynamo effects.     

跨声速风扇叶片的静态气动弹性问题

使用时域的流固耦合数值计算方法,研究了跨声速风扇叶片在气动力和离心力共同作用下的静态气动弹性问题,分析了叶片在不同工况下的变形规律及叶片变形对整体气动性能的影响.NASA rotor 67的静态气动弹性计算说明气动力对叶片最大变形的贡献达13.07%, 而且叶片变形明显地改变了通道激波的位置和强度.宽弦空心跨声速风扇叶片的静态气动弹性计算说明叶片变形对总体气动效率的影响为0.15%~ 0.5%,其中气动力对变形贡献在叶片尖部的前缘可达41%,考虑气动力引起的变形使得该风扇的流量增大,气动特性线整体向右偏移.计算结果说明:气动力的非线性对跨声速风扇叶片静态变形问题有显著的影响,工程实践中从设计叶型到制造叶型的反扭过程应该采用流固耦合方法以得到更准确的叶型.