A novel method to improve the performance of heatexchanger——Temperaturefields coordination of fluids

The methods to enhance the heat transfer in heat exchanger may be classified into two levels: one is to improve the heat transfer coefficient; the other is to upgrade the whole arrangement of the heat exchangers. For the second level, the performance of heat exchanger can be upgraded by increasing the coordination degree between the temperature fields of cold and hot fluids. When the temperature distributions are similar to each other, the temperature difference field (TDF) is more uniform, which means that the temperature fields are more coordinated with each other. For the cross-flow heat exchanger, rearrangement of the heat exchange surface area should improve the heat transfer effectiveness, which is even equal to that of the counter-flow heat exchanger when the surface area is reassigned optimally. For the multi-stream heat exchanger, the thermal performance is also dependent on the uniformity of the TDF, and the parallel-flow arrangement may achieve higher heat exchange effectiveness than the counter-flow arrangement, which indicates that the performance of heat exchanger depends on the coordination degree of temperature fields instead of the flow arrangement.     

New method of designing anti-slide piles——the strength reduction FEM

At present,the thrust of an anti-slide pile can be worked out with some calculation methods. However,the resistance in front of the pile,the distributions of resistance and thrust,and appropriate pile length cannot be easily obtained. In this paper,the authors applied the strength-reduction finite element method (FEM) to several design cases of anti-slide piles. Using this method,it is possible to take the pile-soil interactions into consideration,obtain reasonable resistance in front of pile and the distri...     

A new method of identifying and locating gross errors——Quasi-accurate detection

A new idea and a distinctive method have been proposed, which concern real errors and their estimators. By using the idea of "Quasi-Stable Adjustment" created by Prof. Zhou Jiangwen for reference, the rank-deficient equations on real errors are resolved by adding the conditions under which the minimum of the norm of the real errors of the quasi-accurate observations is restrained. The formulae and the scheme of the new method called "quasi-accurate detection of gross errors (QUAD)" are presented. By using this method, not only multiple gross errors can be identified and located exactly with these estimators calculated accurately, but also the precision of the estimators is able to be evaluated strictly. This method may be suitable to dealing with the gross errors existing in various fields of science and engineering.     

A novel method to improve the performance of heat exchanger——Temperature fields coordination of fluids

The methods to enhance the heat transfer in heat exchanger may be classified into two levels: one is to improve the heat transfer coefficient; the other is to upgrade the whole arrangement of the heat exchangers. For the second level, the performance of heat exchanger can be upgraded by increasing the coordination degree between the temperature fields of cold and hot fluids. When the temperature distributions are similar to each other, the temperature difference field (TDF) is more uniform, which means that the temperature fields are more coordinated with each other. For the cross-flow heat exchanger, rearrangement of the heat exchange surface area should improve the heat transfer effectiveness, which is even equal to that of the counter-flow heat exchanger when the surface area is reassigned optimally. For the multi-stream heat exchanger, the thermal performance is also dependent on the uniformity of the TDF, and the parallel-flow arrangement may achieve higher heat exchange effectiveness than the counter-flow arrangement, which indicates that the performance of heat exchanger depends on the coordination degree of temperature fields instead of the flow arrangement.     

Computation of one—dimensional consolidation of double layered ground using differential quadrature method

The authors give the solution to the problem of one-dimensional consolidation of double-layered ground with the use of the differential quadrature meahod.Case studies showed that the computational results for pore-water pressure in soil layer agreed with those of analytical solution;and that in the computationsl re-sults for the interface of soil lwyer also agreed with those of the analytical solution except for the small discrep-ancies during shortly after the start of computation.The advantages of the solution presented in this paper are that compared with the analytical solution,it avoids the cumbersome work in solving the transcendental equation for eigenvalues,and in the case of the Laplace transform solution,it can resolve the precision prob-lem in the numerical solution of long time inverse Laplace transform.Because of the matrix form of the solution in this paper,it is convenient for formulation computational program for engineering practice.The formulas for calculating double-layered ground consolidation may be easily extended to the case of multi-layered soils.     

Dispersive bubble wall—a new method of flow control in tundish

Tundish is the last refractory vessel in the steelmaking process. The fluid flow phenomena in tundish have a strong influence on the separation of non-metallic inclusions. The dispersive bubble wall (DBW) is a new method in tundish metallurgy. A water model of a multi-strand tundish has been set up based on the Froude number and Reynold number similarity criteria. The effect of DBW+weir on the flow pattern has been studied. The results show that this new structure of DBW+weir is beneficial not only to uniform the temperature among different submerge entry nozzles but also to separate non-metallic inclusions from liquid steel. The DBW can capture the particles of non-metallic inclusions and make them float up to the surface.     

Cryogenic induced phase separation of chitosan solution——A novel method for preparation of membrane with high porosity

The chitosan porous membrane was prepared by extending the principle of thermally induced phase separation (TIPS) for the polymer-diluent system to the polymer solution at ambient temperature to carry out the cryogenic induced phase separation (CIPS). The porous membrane obtained was characterized by scanning electron microscopy (SEM) and gas permeability. It was found that a specific lacy pore structure morphology corresponding to the TIPS' solid-liquid phase separation was formed in the demixing process and the porosity could be more than 70%. The research of demixing mechanism and membrane-formation process showed that the membrane was stacked through porous lamella. The porosity of membrane increases and the pore diameter decreases with increasing solidifying temperature. Both the porosity and pore diameter decrease with the chitosan concentration increase.     

A new hybrid method—combined heat flux method with Monte-Carlo method to analyze thermal radiation

A new hybrid method, Monte-Carlo-Heat-Flux (MCHF) method, was presented to analyze the radiative heat transfer of participating medium in a three-dimensional rectangular enclosure using combined the Monte-Carlo method with the heat flux method. Its accuracy and reliability was proved by comparing the computational results with exact results from classical "Zone Method".     

南美地区油气地质特征及常规油气资源潜力

在分析南美油气地质特征的基础上,进行南美主要含油气盆地待发现常规油气资源评价,总结待发现油气资源分布规律,探讨其勘探前景。结果表明,受4大板块碰撞影响,南美沉积盆地可分成弧前、弧后、前陆、内克拉通和被动陆缘盆地5种类型。南美油气成藏条件优越,烃源岩以中新生界海相-陆相泥岩为主,生烃潜力大。储层以白垩系和第三系碎屑岩和碳酸盐岩为主,分布广泛。盖层中新生界区域性泥岩和盐岩为主,封堵能力强。采用以成藏组合为基础评价单元的资源评价方法,将南美65个盆地共划分出152个成藏组合,并进行了资源评价。预测南美65个主要含油气盆地的待发现石油可采资源量为263716MMB,待发现凝析油可采资源量为7405MMB,待发现天然气可采资源量为559020BCF。待发现油气资源在平面上呈“两带”展布、“两中心”富集特征;在纵向上主要富集于白垩系和第三系。被动陆缘盆地和前陆盆地是南美未来油气勘探的两个重点领域,其中深海和前陆冲断带是主要勘探方向,巴西、委内瑞拉是重点关注国家。     

混合气藏类型划分及成藏模式探讨

混合气藏是常见的天然气藏类型,实用的类型划分及成藏模式的建立是该类气藏定量研究的基础。根据端元气的来源,对混合气藏类型进行了划分,并结合实例建立了相应的成藏模式。研究结果表明,常见的混合气藏可划分出两大类4小类:(1)异源混合气藏,指不同气源岩(灶)生成天然气的混合,其中包括异源岩混合气藏和异源灶混合气藏两类;(2)同源不同阶混合气藏,按母质类型分为煤型不同阶和油型不同阶两类。对塔里木、鄂尔多斯、四川等盆地典型气藏解剖结果证明,多套有效气源岩、沟通圈闭和源岩(灶)的通道是异源混合气藏形成的基础;而气源岩多期次演化生气、持续有效的圈闭是同源不同阶混合气藏形成的重要条件。分析认为,具有多套源岩供气的轮南凸起、川东高陡褶皱带是发育异源混合气藏的有利地区;而成藏过程复杂的库车坳陷则是同源不同阶混合气藏发育的有利地区。     

用射频低温氧化法去除未熟烃源岩中的有机质方法研究

利用GP0 2 A高频感应加热设备产生高频磁场 ,等离子体在高频磁场中激活氧气形成活性氧 ,活性氧在低温低压下氧化烃源岩中的有机质 ,从而达到去除有机质并确定其含量的目的。采用射频低温氧化法对我国 7个盆地未熟烃源岩进行了有机质去除的实验 ,结果表明 ,在最佳条件下用 2 0～ 4 0h可把未熟烃源岩中的有机质去除 ,我国 7个盆地未熟烃源岩中有机质的质量含量为 1.5 3%～ 3.17%。     

裂谷盆地火山活动与油气藏的形成

我国东部裂谷盆地主要生储油层系中常发育有基性浅成侵入岩、火山岩和火山碎屑岩。在火成岩发育区常见油气富集 ,并伴有非烃气藏。喷发在生油岩沉积环境中的玄武岩及其火山碎屑岩可以改变有机质富集状况 ;侵入生油层的辉绿岩等可以使局部具有特殊的油气生成能力 ;火山活动放出的二氧化碳等非烃气体可以直接形成气藏。研究发现 ,火成岩发育区的生油岩具有早熟和油气生成量特别大等特点 ;火成岩发育区一般是盆地内构造应力低值区 ,也是圈闭和油气藏集中发育区。此外 ,火成岩及相关油气藏具有储集空间发育、油气充注率高、油气保存条件好等优点。以东营凹陷等火成岩发育区为实例 ,分析并阐明了有关问题     

中国边缘海盆地构造演化与油气分布富集规律

中国边缘海盆地处在欧亚、印度-澳大利亚及太平洋三大板块相互作用之新生代最活跃区域,其中,南部边
缘海盆地尚受南海裂解扩张作用等多种因素的深刻影响,形成了具有断拗双层结构不同类型伸展型或伸展、走滑、挤
压复合型盆地,沉积充填了古近纪断陷裂谷早期中深湖相地层及其烃源岩、古近纪断陷晚期煤系地层及烃源岩、新近
纪拗陷期海相地层及其烃源岩,为油气形成奠定了雄厚的物质基础。受区域地质背景影响,边缘海盆地地壳性质及厚
度从陆缘区到深海洋盆区具有逐渐递变的特点;盆地沉降沉积中心亦逐渐向深海洋盆迁移,导致其大地热流及地热场
向洋盆区逐渐升高增强,加之与晚期新构造运动和烃源供给系统时空上的相互耦合配置,最终控制了边缘海盆地油气
分布富集规律。     

用生油岩生烃动力学模型计算生油气量

本文采用埋藏较浅的未成熟的东濮生油岩样,在岩石评价仪上进行不同升温速率的热解模拟实验,用Friedman方法处理,求得一系列在不同生烃率时不同的动力学参数。将此样品热解生烃动力学模型与该地区沉积速率、地温梯度等地质参数结合,用龙格-库塔法计算出在天然地质条件下,不同埋深处生油岩的生烃率及已生成油气量的数值解。     

深层碎屑岩含油气储层发育特征

基于深层油气藏的最新数据,对世界范围内深层碎屑岩油气藏富集规律及储层发育特征进行了统计分析.中南美和北美(不包括美国本土48州)深层碎屑岩发现的油气探明和控制(2P)可采储量最多,其中北美发现的石油2P可采储量最多,而中南美发现的天然气和凝析油2P可采储量最多.全球深层碎屑岩油气最富集的六大盆地依次为墨西哥湾、东委内瑞拉、阿拉伯、南里海、塔里木和圣克鲁斯-塔里哈盆地.在深层条件下,尽管储层通常表现为物性整体差,但仍可发育优质储层.深层油气勘探应立足于对“甜点”的预测,重点考虑颗粒薄膜、孔隙流体超压和盐岩发育对深层砂岩储层原生孔隙的保存作用.     

平庄盆地的石油地质特征

为了解平庄盆地烃源岩的赋存特征,结合地质勘查资料,根据沉积学、地球化学理论,分析了该盆地的石油地质特征。结果表明,平庄盆地内发育有三套烃源岩,分别归属九佛堂组、沙海组、阜新组,前两者是构成盆地的主要烃源岩;烃源岩主要形成于半深湖一深湖,部分形成于浅湖、闭塞湖湾及湖沼,其类型以暗色泥岩、油页岩、泥质白云岩等为主;盆地生储盖组合以侧变式为主,油气的圈闭类型主要为断背斜。该结果为平庄盆地的基础地质研究及石油地质勘查提供了参考。     

塔里木盆地寒武纪早期地质背景及对烃源岩发育的控制

塔里木盆地寒武系油气勘探的突破很大程度上取决于烃源岩的发育和分布状况.基于古气候、生物发展的分析,认为早寒武世具有发育烃源岩的条件.寒武系沉积古地形分析显示,塔里木盆地寒武系基底存在古隆起,从台地中心到深海盆地,仍发育泻湖,这些为烃源岩的发育提供了物质条件和古地理条件,古隆起提供了泥质来源,深海盆地和闭塞海湾提供了烃源岩沉积环境,也控制了烃源岩分布.同时,围绕古隆起应该发育粗粒碎屑沉积物,是未来除白云岩和灰岩储层以外的、值得重视的另一类储层.     

坳陷湖盆湖泛层沉积特征及其石油地质意义——以鄂尔多斯盆地三叠系延长组为例

以鄂尔多斯盆地延长组为例,运用高分辨率层序地层学理论,综合利用露头、岩心、测井等资料,在延长组内识别出了6层三级层序级别的湖泛层(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ),研究了其沉积相类型、沉积厚度及其平面展布等沉积特征,从发育层位、露头、岩电响应等方面建立了其识别标志.研究结果表明,湖泛层主要具有4方面的石油地质意义:①湖泛层具有在测井和地震资料上易识别和对比的特征,可作为湖盆层序地层划分和对比的辅助标志层,对湖盆层序地层研究具有一定辅助作用;②利用湖泛泥岩类型及其厚度平面展布特征,反映不同时期湖水分布和演化规律;③借助湖泛层厚度沉积中心的分布和迁移,研究湖盆沉积洼陷的分布和迁移规律,对认识整个湖盆的演化具有重要意义;④湖泛层作为油藏的主要烃源岩和盖层,其时空分布特征控制着油藏组合类型和成藏规律.