涡轮流量计前导流件有限元计算分析

对涡轮流量计关键部件之一前导流件运用NX THERMAL/FLOW进行有限元计算分析,得出流量分离导致的大涡旋尾迹区易出现在前导流件尾部区域、前导流件叶片形状对此处流体速度变化具有较大影响的结论,为涡轮流量计和前导流件的设计提供了理论依据。     

热处理对砂型铸造Mg-Gd-Y合金微观组织和力学性能的影响

通过金相观察(OM)、扫描电镜(SEM)以及拉伸测试系统地表征和研究了热处理对砂型铸造Mg-Gd-Y合金微观组织和力学性能的影响。研究表明:固溶态GW94、GW74、GW44合金主要由α-Mg过饱和固溶体、铸态残留相Mg5(Gd,Y)以及固溶过程形成的方块相组成。随着Gd含量的增加,固溶态Mg-Gd-Y合金中方块相的体积分数不断增加;在同一时效温度下,合金达到时效峰值的时效时间缩短;室温下拉伸的固溶态、时效峰值态合金以及200和250℃下拉伸的时效峰值态合金的抗拉强度和屈服强度不断提高(固溶态合金屈服强度先降低后升高),但是伸长率却是不断降低。时效峰值态GW94合金表现出优越的力学性能,室温时其抗拉强度和屈服强度分别为300、247 MPa,而伸长率仅为0.9%;200和250℃拉伸时,时效峰值态GW94合金抗拉强度、屈服强度和伸长率分别为329、234 MPa和2.6%以及312、233 MPa和2.7%。时效峰值态GW94、GW74合金出现抗拉强度随温度升高而升高的反常力学行为。     

运动的核弹比静止的核弹威力小?——多普勒效应、红移、光行差和动体的质能当量关系

证明爱因斯坦立足于光速不变假设和长度收缩假设的洛伦茨变换未能正确地解释多普勒效应、红移和光行差现象;他也未能给出正确的动体的质能当量关系.作者立足于完全符合相对性原理的伽利略变换,成功地解决了上述问题.     

壳体内腔大深度T型刀加工方案分析

对于外形、内腔结构复杂,零件体积大,材料去除率高等特点的壳体,锻件加工要求所编制的数控程序异常复杂,数据庞大,手工编程难以编制程序。采用UGCAM作为编程手段,利用3维实体辅助编程技术解决此类问题。     

椭球台高杆灯风荷载的实验研究

通过风洞实验研究了多钝体高杆灯在不同水平风向角和竖向风向角下的力与力矩系数。实验结果表明在一定的风向角下，法向阻力系数Cdmax=1.030,法向弯曲力矩系数Cmmax=-0.940,轴向力系数Camax=0.504和Camin=-0．600。     

单晶高温合金叶片用熔模壳型的研制

介绍了一种加矿化剂的单晶壳型。它具有高强度、壁厚薄而均匀的特点，已应用该壳型成功浇注了单晶叶片。     

Dynamics of a spacecraft and normalization around Lagrangian points in the Neptune–Triton system

The problem of a spacecraft orbiting the Neptune–Triton system is presented. The new ingredients in this restricted three body problem are the Neptune oblateness and the high inclined and retrograde motion of Triton. First we present some interesting simulations showing the role played by the oblateness on a Neptune’s satellite, disturbed by Triton. We also give an extensive numerical exploration in the case when the spacecraft orbits Triton, considering Sun, Neptune and its planetary oblateness as disturbers. In the plane a × I (a = semi-major axis, I = inclination), we give a plot of the stable regions where the massless body can survive for thousand of years. Retrograde and direct orbits were considered and as usual, the region of stability is much more significant for the case of direct orbit of the spacecraft (Triton’s orbit is retrograde). Next we explore the dynamics in a vicinity of the Lagrangian points. The Birkhoff normalization is constructed around L₂, followed by its reduction to the center manifold. In this reduced dynamics, a convenient Poincaré section shows the interplay of the Lyapunov and halo periodic orbits, Lissajous and quasi-halo tori as well as the stable and unstable manifolds of the planar Lyapunov orbit. To show the effect of the oblateness, the planar Lyapunov family emanating from the Lagrangian points and three-dimensional halo orbits are obtained by the numerical continuation method.     

A Structured Mesh Euler and Interactive Boundary Layer Method for Wing/Body Configurations

To compute transonic flows over a complex 3D aircraft configuration, a viscous/inviscid interaction method is developed by coupling an integral boundary-layer solver with an Eluer solver in a ＂semi-inverse＂ manner. For the turbulent boundary-layer, an integral method using Green＇s lag equation is coupled with the outer inviscid flow. A blowing velocity approach is used to simulate the displacement effects of the boundary layer. To predict the aerodynamic drag, it is developed a numerical technique called far-field method that is based on the momentum theorem, in which the total drag is divided into three component drags, i.e. viscous, induced and wave-formed. Consequently, it can provide more physical insight into the drag sources than the often-used surface integral technique. The drag decomposition can be achieved with help of the second law of thermodynamics, which implies that entropy increases and total pressure decreases only across shock wave along a streamline of an inviscid non-isentropic flow. This method has been applied to the DLR-F4 wing/body configuration showing results in good agreement with the wind tunnel data.     

钛合金熔模精铸氧化锆陶瓷型壳／金属界面反应研究

通过实际浇注和真空扩散连接分别制取了钛／型壳界面，借助ＳＥＭ、ＥＰＭＡ和显微硬度仪等分析测试手段对所得界面进行了深入研究，初步提出了以Ｚｒ、Ｏ元素向钛基体内的扩散为主导的界面反应机制。实验结果表明，界面反应并非在整个界面上均衡推进，而是在浓度、温度、能量起伏、以及陶瓷颗粒位向适宜的区域优先发生界面反应     

人体热调节的有限元分析

本文根据人体的热调节机制建立了二维人体热调节的有限元模型，并设计了相应的实验对该模型进行了验证，实验结果与计算结果吻合较好，本模型对于以人体－环境热交换为内容的工程实践和理论研究有较高的应用价值。