油-水两相流流变特性研究

应用细管式流变仪对含水稠油流变性进行了实验研究,得出不同温度、不同含水率以及不同剪切率下的流变规律和计算方法。在实验范围内含水稠油为非牛顿流体。随着温度的升高,流变指数增大而稠度系数减小;随着含水率的增加,流变指数和稠度系数不断减小。含水稠油的温度在90℃以下时,其n值都小于1,此时含水稠油的流变特性为假塑性流体,而且,温度越低,n值越小,表示含水稠油的流变特性偏离牛顿流体特性越远,假塑性越强。     

原油管道停输再启动实验研究

在实验室内建立了管流实验装置,测定大庆原油流变特性以及进行停输再启动的实验研究。对原油流变特性的测定大多是在旋转黏度计中进行的,而原油在旋转黏度计中是拖动流,在管路中为压力流。管流实验装置测量的原油流变特性曲线更符合实际管道原油的流变特性。分析了停输前流量、启输流量、原油出站温度、环境温度对启输过程的影响。由试验结果以及模拟结果分析可知,对停输过程温度的计算偏低,再启动压力值偏大。对解决东北管网的低输量问题具有指导意义和实际的应用价值。     

渤中稠油乳状液的流变性实验研究

此项研究的目的在于揭示含水率、压力和温度等对稠油乳状液流变特性的影响.实验结果表明,油品乳状液的反相点大约在含水率70%左右,温度对乳状液黏度和流变性影响较为明显,压力对乳状液黏度和流变性影响不大.     

山岭隧道围岩流变参数识别及应用研究

依托西康高速公路油房湾小净距隧道工程,对隧道围岩--石灰岩的流变特性进行了试验研究,给出了流变变形特性曲线,建立了能描述油房湾隧道围岩流变变形特征的流变模型.基于流变反演理论,获得了相应模型的弹性性能参数(岩体弹性体积模量、剪切模量和变形模量等)和流变参数及长期弹性模量等.利用反演流变模型及参数,并结合油房湾小净隧道工程地质特点及施工方案进行了三维流变数值模拟分析.结果表明,小净距隧道围岩变形时效特性规律基本符合H-K模型特征,表明基于试验辨识的H-K蠕变模型和反演参数的数值模拟能超前做出科学预测和定量评价,为山岭小间距隧道的设计和施工提供了可靠的参考信息和理论依据.     

泵送浆体管道中屈服伪塑性体摩阻损失的研究

根据浆体流变曲线位置对浆体进行了分类，给出了各种浆体的流变方程式，推导出屈服伪塑性体摩阻系数计算公式及各种浆体切变率和粘度的通用计算公式。最后举例说明了上述计算公式的使用方法。     

特石管线超稠油黏温特性实验分析

辽河油田曙光特油2号站至石化分公司输油管线输送原油为超稠油。超稠油的输送过程中,需要进行加热以降低黏度。为了降低企业运营成本,需要对稠油管道进行优化设计,这就需要掌握目前管道中超稠油的黏温特性。在利用HAAKE RV-3旋转黏度计测出不同温度超稠油的黏度后,进行数据分析,得出超稠油流变方程与黏温指数,用以指导超稠油管道的优化工作。     

CFD数值模拟在分离海砂碎贝壳中的应用

将贝壳砂混合液通过结构设计,获得一定黏度值的强制旋涡非牛顿流场,利用砂与贝壳在流场中的流态差异,实现有效分离。通过CFD仿真计算调整多相流获得最佳的输入输出参数,制定出符合目标的多相流分离方案,并在流体仿真的基础上,加工一套与仿真模型基本一致的技术试验装置,以验证三相分离的效果。     

抚顺石油一厂渣油管道流动特性的研究

采用RV2旋转黏度计测定了石油一厂渣油在 6 0～ 14 0℃范围的流动特性参数 ,当油温在 90℃以上时 ,渣油为牛顿流体 ,油温低于 90℃时 ,渣油为非牛顿流体 ,而且油温越低非牛顿特性越强。渣油的黏温关系与原油类似 ,其黏温曲线可分为放射段和直线段 ,但非牛顿特性强于原油。     

改善稠油流动性的方法及应用

针对稠油的高黏性、易乳化等特点及容易造成管道等生产设备的堵塞、高能耗等技术难题,加快稠油降黏新理论的研究成为解决稠油安全经济输送、降低稠油生产成本的重点.介绍了目前常用的几种稠油管输减阻方法,阐述了它们的工作原理,对比分析了它们的优缺点.同时,探讨并总结了稠油冷采中产生的泡沫油流使其采收率提高的原理以及泡沫油流的组成,提出了应用泡沫油流改善稠油的流动性的思路,对提高稠油的管输效率具有显著的意义.     

稠油掺稀后混油黏度计算方法的研究

稀释输送是传统的稠油降黏输送方法,因其工艺简单,降黏效果在管输过程中较稳定,一直在国内外得到广泛应用。但稠油中加入稀油后其混油黏度又是一个难点,混油黏温数据是摩阻计算的重要参数,是输油管道设计和运行管理的重要参数,其准确性对水力计算结果至关重要。对混合原油的黏度计算,国内外学者提出了不少经验公式、半经验公式以及计算图表,且大多是利用实验数据通过线性回归得到的,每种模型都有一定的适用范围。通过对Cragoe模型进行修正,得出稠油掺入稀油黏度计算需分段选择模型的结论。     

基于CAGD的管道摩擦系数确定方法

采用计算机辅助几何设计的方法 (CAGD法 ) ,对管道摩擦系数曲线图进行计算机精确描绘 ;利用VisualBasic和AutoCAD混合编程进行计算机准确查图 ,VisualBasic编程进行界面设计和前台运算 ,AutoCAD技术进行后台图形处理 ,准确确定给定条件下的管道摩擦系数     

X52焊缝失效评定曲线

失效评定曲线被广泛应用于管道的断裂评定,针对严重影响国内在役老管道安全运行的焊缝问题,建立焊缝失效评定曲线.以在役老管道常用管材X52为例,采用R6方法建立焊缝失效评定曲线(选择3曲线),并与R6选择1曲线和选择2曲线比较,表明选择3曲线的精确性对于在役管道焊缝失效精确评估的重要性.给出了3种焊缝材料特性的失效评定曲线...     

Measurement uncertainty determination and curve-fitting algorithms for development of accurate digital maps for advanced driver assistance systems

Digital maps can provide support for numerous advanced driver assistance systems (ADAS) aimed at improving road safety. These new uses require more highly detailed and precise maps. The use of a datalog vehicle to collect roadway geometry data can fulfil these specifications. This paper presents fast, accurate measurement with an on-board inertial system together with a method to evaluate measurement uncertainty, particularly for any variables obtained indirectly. It also presents an algorithm for segmentation and fitting geometric curves to the experimental points, following current highway design standards. The algorithms have been applied to real road measurements. Segmentation has been done in straight alignments, circular curves and transition curves whose characteristic parameters are calculated. It has been seen that with a very small data set it is possible to reconstruct the measured geometry with few discrepancies regarding the experimental points.     

油井地面集输管停掺水温降数值模拟

掺水混输不加热集油工艺正不断发展完善,集输管停掺水温降过程是指导该技术实施的重要依据,掌握其降温规律对确定安全停掺水时间、再掺水启动方案和停掺水检修安排都有着十分重要的意义。基于计算流体动力学理论,利用FLUENT对油井地面集输管道停掺水后的温降过程进行数值模拟,得出不同含水率与不同初始油温下管内油品的温降曲线。根据管轴中心温降曲线可将整个降温过程分为3个阶段,第一阶段温降速度最快,其余两阶段较慢,第一阶段自然对流作用占主导地位,第二阶段管壁油品开始凝结,自然对流逐渐消失,第三阶段传热方式仅剩导热,且作用较弱,整个管内油品的凝结时间长短与停掺水初始油温及管内液体的含水率有关。通过模拟计算可得详细的温降过程,为实际停掺水不加热集油工艺设计提供参考依据。     

Development of transitioned vertical curve II Sight distance

The mathematical properties of a new vertical curve that consists of a transition curve (cubic polynomial), a parabolic curve, and another transition curve have been presented in a companion paper. The present paper addresses the sight distance characteristics of this new curve, called transitioned vertical curve. The minimum sight distance and the required curve length are analytically derived for both crest and sag curves, considering various cases related to the minimum sight distance and the lengths of transition and parabolic curves. Using the developed analytical models, example design graphs are established for the length requirements of the transitioned vertical curve based on the upper range of stopping sight distance presented by the American Association of State Highway and Transportation Officials. The transitioned vertical curve, which resembles the spiraled horizontal curve commonly used in practice, represents an alternative to the simple vertical curve especially for sharp vertical alignments.     

Development of transitioned vertical curve I Properties

Introducing spiral curves before and after horizontal circular curves has been widely accepted to enhance traffic safety, highway esthetics, sight distance, and driver comfort. Though, vertical curves are still designed as parabolic curves that are connected directly to the tangent (without transitions). In this paper, a cubic polynomial is used to develop a vertical transition curve before and after the parabolic vertical curve. The resulting curve, called transitioned vertical curve, consists of transition-parabolic-transition segments. Detailed mathematical formulation and derivation of the instantaneous elevation, grade, rate of curvature, and offset from the first tangent at any point are presented. The highest (or lowest) point on a transitioned crest (or sag) vertical curve, where the instantaneous grade equals 0, is determined as it is of particular importance in highway drainage design. The minimum length of a transition curve is derived based on the criterion of driver comfort. In addition, guidelines are provided to identify the conditions where the drainage of surface water on transitioned curves can be a concern. Finally, the layout of the transitioned vertical curve is described and illustrated using two numerical examples. The new transitioned vertical curve, which exhibits striking similarities to the spiraled horizontal curve, should enhance the design of highway vertical alignments.     

盾构隧道通用楔形管片排版系统的核心算法研究

盾构隧道通用楔形管片是通过前后两环的相对旋转来拟合线路中的直线和曲线要素,简化了模板设计,通用性强、质量容易保证。通用楔形管片拼装设计的关键是根据线路的平、竖曲线要素和偏差要求确定环宽和楔形量,而每一环衬砌的偏差计算是通过排版来实现的。文章对通用楔形管片排版的主要步骤和核心算法作了介绍,其中包括平、竖曲线上的坐标法定点算法、线路上理想点的二分法求值算法,以及空间任意点绕任意轴旋转的计算机图形学算法。文章最后介绍了一个盾构区间隧道的排版过程及结果。     

屈服假塑性流体管流流动及传热规律研究

结合屈服假塑性流体的本构方程、管流力平衡关系式以及非牛顿流体的能量方程，得出了屈服假塑性流体管流速度分布及温度分布。研究结果表明：由于屈服应力的作用，管中心存在柱塞流动，柱塞的半径与屈服应力成正比，与压力梯度成反比；管流流量随屈服应力的增大而减小；柱塞内温度一致，从柱塞边界到管壁，温度逐渐减小，而且越靠近管壁，温降梯度越大。     

On the fundamental diagram and supply curves for congested urban networks

Macroscopic fundamental diagrams (MFD) of traffic for some networks have been shown to have similar shape to those for single links. They have erroneously been used to help estimate the level of travel in congested networks. We argue that supply curves, which track vehicles in their passage through congested networks, are needed for this purpose, and that they differ from the performance curves generated from MFD. We use a microsimulation model, DRACULA and two networks, one synthesizing the network for Cambridge, England, and one of the city of York, England, to explore the nature of performance curves and supply curves under differing patterns of demand.We show that supply curves differ from performance curves once the onset of congestion is reached, and that the incorrect use of performance curves to estimate demand can thus seriously underestimate traffic levels, the costs of congestion, and the value of congestion relief measures. We also show that network aggregated supply curves are sensitive to the temporal distribution of demand and, potentially, to the spatial distribution of demand. The shape of the supply curve also differs between origin–destination movements within a given network.We argue that supply curves for higher levels of demand cannot be observed in normal traffic conditions, and specify ways in which they can be determined from microsimulation and, potentially, by extrapolating observed data. We discuss the implications of these findings for conventional modelling of network management policies, and for these policies themselves.     

油田内部热油管道最佳操作参数的快速确定

由于油田内部热油管道操作参数上的不合理,给油田生产造成了不必要的能量损耗。利用管道分段的方法,通过热力和水力计算,生成出站参数曲线图,方便快捷的为油田内部的热油管道确定最佳的出站（管道起点）加热温度和出站压力,减少能源的浪费。计算中,考虑了流量、含水量、黏度变化等因素,为流量和含水量不断变化的油田内部加热输油管道的优化运行提供参考。