A note on the thermal stability of a reactive non-Newtonian flow in a cylindrical pipe

The effect of variable viscosity and viscous dissipation on the thermal stability of a one-step exothermic, reactive non-Newtonian flow in a cylindrical pipe was considered assuming negligible reactant consumption. The governing equations; momentum and energy equations, which are coupled due to the dissipative term in the energy equation, were solved by closed-form and approximate techniques respectively. We obtained closed-form solutions for the momentum equation via the Homotopy analysis method(HAM), while the resulting energy equation was analysed for thermal stability via the variational technique. Parametric analysis of the solutions were conducted on the dimensionless velocity (v(r)), the critical Frank-Kamenetskii parameter(δ_cr) and the critical temperature(θ_cr) and expressed graphically and in tabular forms.     

螺杆泵在稠油出砂井中的应用

本文介绍了螺杆泵采油系统基本结构和工作原理，根据螺杆泵在稠油出砂井中的现场应用，分析了螺杆泵现场应用效果以及现场施工时要求，展现了螺杆泵采油系统在高粘稠油和出砂井等方面良好的现场应用前景。     

大庆、大港原油对降凝剂的感受性及其非烃组份对降凝效果的影响

选用最常用的两类原油降凝剂,即乙烯-醋酸乙烯酯类共聚物和丙烯酸高碳醇酯类聚合物,以大庆、大港原油为研究对象,考察了原油降凝剂及其有关非烃组份对降凝剂降凝效果的影响.发现大庆原油对许多降凝剂之所以没有良好的感受性,是因为大庆原油中存在着一种对某些降凝剂的降凝效果有强烈抑制作用的胶质.     

侧钻井防砂工艺技术

针对铡钻井井身结构的特点，简要介绍了两种稠油侧钻井防砂技术的机理和内容。其中，在小直径筛管防砂技术中，防砂筛管和封隔器的设计是主要的；而通过室内试验证明，高温人工井壁完全能够满足现场防砂要求。     

稠油油藏蒸汽吞吐年油汽比的变化规律及其预测方法

以辽河油区已投入吞吐开采稠油油藏实际一切数据为基础，总结了年油汽比变化规律，建立其动态预测的数学模型，并用推广递推梯度方法，对模型中的参数进行了估计。     

Analytical and numerical studies on viscous energy dissipation in laterally driven microcomb structures

Numerical and analytical studies on viscous air damping in laterally oscillating microcomb structures are discussed in this work. Previous investigators modeled this type of flow field using Couette and Stokes flow models. The numerical simulation results demonstrate that the flow is much more complex and quite different from the Couette or Stokes flow. The pumping and sucking motions at the edges of the oscillating electrode create a fluid brake. This fluid brake retards the horizontal movement of the flow and generates a strong vortex in the region between the oscillating electrode and the base material, which has not been reported before. The deceleration of the fluid also increases the velocity gradient on the surfaces of the oscillating electrode, which gives rise to a higher damping. The numerically predicted damping is about 2.8 times larger than that predicted by the Stokes flow model.     

Real-time dynamic substructuring testing of viscous seismic protective devices for bridge structures

This paper presents a real-time dynamic substructuring (RTDS) test program carried out on bridge structures equipped with two innovative viscous seismic protective devices: a seismic damping unit and a shock transmission unit. In the RTDS tests, the seismic protective units were physically tested in the laboratory using a high performance dynamic actuator imposing, in real time, the displacement time histories obtained from numerical simulations being run in parallel. The integration scheme used in the test program was the Rosenbrock-W variant, and the integration was performed using The MathWorks’ Simulink and XPC target computer environment. The numerical counterpart included the bridge columns and the additional energy dissipation properties. The nonlinear response of these components was accounted for in the numerical models. The tests were run under various ground motions, and the influence of modeling assumptions such as damping and initial stiffness was investigated. Finally, the test results are compared to the predictions from nonlinear dynamic time history analyses performed using commercially available computer programs. The results indicate that simple numerical modeling techniques can lead to accurate prediction of the displacement response of bridge structures equipped with the seismic protective systems studied.     

In-plane cyclic behaviour of a new reinforced masonry system: Experimental results

This paper describes the behaviour under cyclic shear compression of an innovative reinforced masonry system, composed of horizontally perforated units, having common steel bars or prefabricated trusses as horizontal reinforcement. At the wall edges or crossings, confining columns for vertical reinforcement are built with vertically perforated units. Experimental tests to obtain information on the in-plane cyclic behaviour of the construction system were performed on masonry panels made of horizontally perforated units and on completed reinforced masonry walls. Tests on the entire system were repeated for two wall aspect ratios and two vertical stress levels, in order to force shear type and flexural behaviour. In particular, this paper presents: (a) results of shear compression tests in terms of strength, ductility parameters, energy dissipation, viscous damping and stiffness degradation, (b) strains and the effectiveness of reinforcement, (c) the influence of various parameters such as axial load, aspect ratio, and reinforcement type on the behaviour of the reinforced masonry walls, and (d) comparison of walls built with and without vertical reinforcement.     

带转向机构HCA在杭州湾跨海大桥斜拉索减振中的应用

杭州湾跨海大桥北航道桥为主跨448m的钻石型双塔双空间索面钢箱梁斜拉桥,通航净空为47m,按双向六车道高速公路设计,设计时速100km/h。为改善行车安全性,国内首次在栏杆外侧设置了风障(高度从近塔4.27m至远塔3.4m),为了确保整桥隽秀的景观前提下开发了带转向机构的拉索减振器,对全桥拉索进行了理论分析和安装减振器后的实桥测试。