全金属螺杆泵漏失机理研究

传统的橡胶螺杆泵采用过盈方式啮合,当压力小于泵的击穿压力之前,泵没有漏失现象,但全金属螺杆泵定转子都是金属材质,且定转子之间采用间隙配合的啮合方式,所以即使在泵正常工作时,漏失也是一直存在的,研究全金属螺杆泵的漏失规律,为研究整个螺杆泵工作特性奠定基础。在同心环缝隙流动基础上充分考虑流体惯性力引起的压降漏失,研究全金属螺杆泵漏失计算通式,在对模型进行验证的基础上,分析漏失模型的影响因素,结果表明全金属螺杆泵漏失量主要受泵本身结构参数和泵送流体密度的影响,其中间隙高度为影响漏失的主要因素。     

全金属螺杆泵漏失机理

传统的橡胶螺杆泵采用过盈方式啮合,当压力小于泵的击穿压力之前,泵内没有漏失现象。全金属螺杆泵定转子都是金属材质,且定转子之间采用间隙配合的啮合方式,故即使在泵正常工作时,漏失也客观存在。研究全金属螺杆泵的漏失规律,为研究整个螺杆泵工作特性奠定基础。在同心环缝隙流动基础上充分考虑流体惯性力引起的压降漏失,研究全金属螺杆泵漏失计算通式,在对模型进行验证的基础上,分析漏失模型的影响因素。结果表明:全金属螺杆泵的漏失主要受泵本身结构参数和泵送流体密度的影响,其中间隙高度为影响漏失的主要因素。     

螺杆泵转子三维运动仿真分析及型线优化设计

利用三维有限元模型计算螺杆泵在过盈条件下的转子运动轨迹,分析在液压条件下液压力对定、转子相互作用的影响,得到液压条件下转子的运动规律,解释螺杆泵在运行过程中转子运动轨迹发生变化的机制。以改善螺杆泵的运行特性、降低扭矩为目的,提出同时改变螺杆泵转子节圆直径与偏心距的型线优化设计方法。结果表明,新方法能够较好地修正螺杆泵转子在定子内部的运动轨迹,提高螺杆泵的举升特性,延长螺杆泵的使用寿命。     

全金属单螺杆油泵工作性能的全参数分析

针对全金属单螺杆泵运行参数和结构参数对其工作性能影响不明确的问题,开展了全金属单螺杆泵运行参数和结构参数对泵工作性能影响的研究,研究中采用了基于FLUENT的全金属单螺杆油泵3D数值分析技术,获得了黏度、转速和级增压值对泵的排量、功率、容积效率和系统效率的影响以及定转子间隙、偏心距和定子导程对泵的排量、功率、容积效率和漏失量的影响,并进一步得出了该结构在稠油热采时宜采用较高转速而稠油冷采时宜采用低转速的结论,此外,得出稠油热采时定转子间隙值宜取0.1~0.3 mm、偏心距宜取5.0~6.0 mm、定子导程宜取170~200 mm;稠油冷采时定转子间隙值宜取0.3~0.5 mm、偏心距宜取4.0~5.0 mm、定子导程宜取110~150 mm。     

螺杆泵特性曲线修正方法研究

螺杆泵实际工作时所处环境的压力、温度、流体介质均与测试条件存在较大差异,导致螺杆泵的水力特性曲线并不能代表螺杆泵的真实特性。很多学者从不同的角度分析过螺杆泵特性曲线的影响因素及修正方法,但目前并未建立一套系统的、可量化的修正模型。为了能够获取螺杆泵实际工作状态下的特性,通过研究转子转速、过盈量、流体黏度、含气量四大因素影响,建立了螺杆泵特性曲线修正模型。结果表明,修正后的特性曲线能够表征螺杆泵的真实特性,为油井选泵提供可靠的参考依据。     

煤层气排采螺杆泵定转子接触有限元分析

为了得到煤层气排采中影响螺杆泵寿命的因素,为进一步优化设计参数提供依据,利用有限元及实验方法对定转子接触状况进行了研究。通过建立螺杆泵定转子二维平面应变模型,以转子上圆心附近位置两点运动轨迹为对象,分别得到了不同转速及不同过盈量下的接触应力拟合方程及曲线,得到了在定子内腔不同接触位置处的剪应力及接触应力云图,并与实验分析结果进行比较。结果表明:定转子间过盈量越大,定转子接触磨损痕迹越深。剪应力分布的范围在直线中心处类似椭圆状,且椭圆长轴与直线约成45°夹角,过盈量越大,椭圆越大。剪应力最大的位置为点接触处,而该处粘着磨损较严重,接触应力最大位置为线接触处,与实验的形貌分析结果一致。     

双热源作用下螺杆泵定子非稳态温度场数值模拟

为了进一步探讨螺杆泵在油气田开发中出现的高温破坏问题,基于汽车滑移理论,采用单向解耦法,以GLB500和DGLB500螺杆泵为例分析定子温度场分布规律及散热性能,研究不同过盈量、转速下的定子增温。结果表明:螺杆泵定子温度场沿长轴对称分布,最高温度点位于定子橡胶衬套厚壁中心处,考虑摩擦生热时,最高温度点沿短轴方向向定子中心偏移;等壁厚螺杆泵散热性能较好且比较均匀,常规螺杆泵长轴方向散热能力优于短轴方向;不考虑摩擦生热时,定子增温与转子转速正相关,随定转子过盈量的增加呈抛物线趋势增加;在双热源作用下,定子增温随过盈量和转速急剧增加,并且等壁厚螺杆泵表现更为敏感。     

基于 SolidWorks 的单头采油螺杆泵有限元分析及其线型优化

利用在SolidWorks软件中建立的螺杆泵定子的三维实体模型,在有限元分析软件COSMOSWorks环境下,进一步建立了定子的有限元分析模型,并分析了定子橡胶衬套内表面在均匀压力作用下其应力、应变和位移的分布规律.结果表明,定子刚体部分的应力较大,应变较小;橡胶衬套部分应力较小,沿其内表面半圆处应变较大,直线段处应变较小;在橡胶衬套内表面,直线段中点处的位移最大,使该直线变成外凸曲线,导致转子与定子之间在该处产生间隙,影响螺杆泵的工作性能.将螺杆泵定子型线的直线段优化成内凸圆弧,通过有限元重分析表明,该处的相对位移均匀,使转T与定子间产生均匀的过盈,从而提高了螺杆泵的工作性能.     

导热管与电机转子过盈联接有限元分析及优化

将导热管安装于电机转子中对转子进行散热,可提高电机的输出效率,而导热管与转子内孔的紧密接触是导热散热的关键因素.通过建立导热管与转子过盈联接的有限元模型,分析过盈量、摩擦因数以及配合长度对导热管与电机转子过盈联接静态和动态性能的影响.结果表明,过盈量和配合长度对结构的静态和动态力学性能影响较大.在有限元分析的基础上,对导热管与电机转子过盈联接最大法向接触应力进行多目标优化,得出导热管与转子最大法向接触应力最小的接触状态,以提高导热管与转子配合的可靠性以及转子轴的寿命.     

基于能量守恒的螺杆泵动态充满程度计算模型及应用

螺杆泵举升作为主要举升方式已得到广泛应用,但受举升介质及工作参数影响螺杆泵性能不能有效发挥,限制了其泵效最大化。本论文针对螺杆泵采油存在的充不满现象,以螺杆泵泵下油管、吸入口和泵腔内液面为研究对象,分别建立相邻两截面间的伯努利方程,确定泵腔内液面高度;并根据转子运动规律,建立泵腔打开体积模型和进入流体体积模型,结合泵腔内液面高度确定螺杆泵的动态充满程度;通过对不同参数的模拟计算分析,动液面、转速是影响螺杆泵充不满的主要因素。现场5口井实际生产效果证明,本论文建立的计算模型误差小于10.3%。     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.