Remarks on Two Approaches to the Horizontal Cohomology: Compatibility Complex and the Koszul–Tate Resolution

The Koszul–Tate resolution is described in the context of the geometry of jet spaces and differential equations. The application due to Barnich, Brandt, and Henneaux of this resolution to computing the horizontal cohomology is analyzed. Relations with the Vinogradov spectral sequence are discussed.     

风化店地区火山岩分辨率和振幅的影响因素

以风化店地区中生界火山油藏为例，分析了影响纵，横向分辨率的因素，提出了改进措施，并探讨火山岩弱反射振幅的形成机制。     

水平连铸圆坯的表面冷收缩率与结晶器锥度

本文给出了铸坯表面冷收缩率的计算方法;锥度与表面纵裂纹的关系及合理锥度的选择。     

水平井偏心环空低速顶替运移机制研究

水平井固井顶替过程中,受限于现场设备,难以实现紊流顶替,而在层流流速区间内,两相流体在偏心环空中运移机制复杂。基于计算流体动力学方法,建立几何模型和数值模型,采用流体体积法对两相流体顶替界面进行追踪,研究了不同顶替流速下水平井偏心环空流体运移机制。结果表明,（1）低偏心度下,1倍隔离液用量能够实现90%顶替效率,而当偏心度大于0.5时,顶替效率相对较低,即使增加隔离液用量,也未能提高顶替效率;（2）针对套管严重偏心情况,将流速由1.0 m/s降低到0.2 m/s,有助于界面平稳发展,并多置换出6.8%钻井液,解决窄边滞留,宽边指进问题;（3）水平井偏心环空固井注替过程存在偏心效应、重力效应、黏滞效应等多方面影响,这些因素相互制约、相互作用,因此,针对现场实际井况,合理设计固井工艺参数,不仅能提高固井质量,还能起到降本增效的作用。     

Scaling Immiscible Displacements in Porous Media with Horizontal Wells

Despite the increase in horizontal well applications, scaling fluid displacement in porous medium with horizontal wells is yet to be fully investigated. Determining the conditions under which horizontal wells may lead to better oil recovery is of great importance to the petroleum industry. In this paper, a numerical sensitivity study was performed for several well configurations. The study is performed in order to reveal the functional relationships between the scaling groups governing the displacement and the performance of immiscible displacements in homogeneous reservoirs produced by horizontal wells. These relationships can be used as a quick prediction tool for the fractional oil recovery for any combinations of the scaling groups, thus eliminating the need for the expensive fine-mesh simulations. In addition, they provide the condition under which a horizontal well configuration may yield better recovery performance. These results have potential applications in modeling immiscible displacements and in the scaling of laboratory displacements to field conditions.     

Heat transfer measurements and correlations for air–water flow of different flow patterns in a horizontal pipe

Heat transfer coefficients were measured and new correlations were developed for two-phase, two-component (air and water) heat transfer in a horizontal pipe for different flow patterns. Flow patterns were observed in a transparent circular pipe using an air–water mixture. Visual identification of the flow patterns was supplemented with photographic data, and the results were plotted on the flow regime map proposed by Taitel and Dukler and agreed quite well with each other. A two-phase heat transfer experimental setup was built for this study and a total of 150 two-phase heat transfer data with different flow patterns were obtained under a uniform wall heat flux boundary condition. For these data, the superficial Reynolds number ranged from 640 to 35,500 for the liquid and from 540 to 21,200 for the gas. Our previously developed robust two-phase heat transfer correlation for a vertical pipe with modified constants predicted the horizontal pipe air–water heat transfer experimental data with very good accuracy. Overall the proposed correlations predicted the data with a mean deviation of 1.0% and an rms deviation of 12%.     

Thermal radiation effect on mixed convection from horizontal surfaces in saturated porous media

An analysis is presented to investigate the effect of radiation on mixed convection from a horizontal flat plate in a saturated porous medium. Both a hot surface facing upward and a cold surface facing downward are considered in the analysis. The conservation equations that govern the problem are reduced to a system of nonlinear ordinary different equations. The important parameters of this problem are the radiation parameter R, the buoyancy parameter B, and the freestream to wall temperature ratio T _∞/T _w for the case of a hot surface or the wall to freestream to wall temperature T _w /T _∞ for the case of a cold surface.     

应用ESPI研究水平热管的自然对流现象

本文应用 Vintens ESPI、全息干涉及新发展的 Video 的全息干涉技术,研究了水平热管的自然对流现象。介绍了这三种技术的光学系统,和关于气体温度场的测量原理和测量结果。与热电偶所测温度值比较,结果相当一致。文中还就可能的测量误差作了定性分析。     

在微粗糙平面上滚动的Chaplygin球的稳定性

本文利用文献[1]的结果,继续讨论 Chaplygin 球在微粗糙平面上滚动的稳定性。严格证明了在粘性和库仓两种磨擦条件下球绕最大惯量主轴滚动的一致稳定性,和在粘性摩擦条件及球的最大与中间主惯量矩十分接近的前提下球绕最小惯量主轴滚动的不稳定性。     

Heat transfer in bubble layers at elevated pressures

Heat transfer with steam condensation under moderate pressure on the surface of a horizontal tube immersed in a bubbling layer was experimentally investigated. A copper test section 16 mm in outer diameter and 400 mm in length was placed in a bubbling column 455 mm in diameter. Experiments were made under pressures of 0.14–0.8 MPa, with void fraction 0.04–0.23, vapor superficial velocities 0.05–0.42 m/s, liquid-wall temperature differences 47–105 K, and heat flux densities 0.12–0.8 MW/m². The heat transfer process in the bubbling layer is shown to be of a high intensity: with moderate values of steam content, heat transfer coefficients reach 12–14 kW/(m² · K). Data obtained showed that the known correlations do not consider the influence of pressure on heat transfer. For the first time, data on radial steam content distribution under pressures higher than atmospheric were obtained by an electroprobe method. A table of experimental data is presented.