二相流体中的二次流与稳定化效应

分析了二次流现象及稳定化效应，并结合二次流产生的条件，从理论上论证了二次流场稳定时的流场特性，这也是二相流体中颗粒沉降的最佳流场。     

二相流体中的二次流与稳定化效应

分析了二次流现象及稳定化效应，并结合二次流产生的条件，从理论上论证了二次流场稳定时的流场特性，这也是二相流体中颗粒沉降的最佳流场。     

真空电弧纳米流体颗粒沉降及悬浮稳定性探讨

具有高度悬浮稳定性的纳米流体在工业应用上,才可确保纳米化的独特性与应用价值。本文旨在以自行发展的真空电弧纳米流体合成系统所制备出的纳米流体,探讨纳米流体中悬浮颗粒的沉降及悬浮稳定性。文中将分析此系统的主要制程参数对所合成Cu及Ti纳米流体悬浮稳定性的影响,如峰质电流、崩溃电压及放电幅等。针对所制备出的纳米流体检测其平均粒径、粒径分布、形貌特性、pH值、接口电位、沉降性及材料结构等特征,同时观察及量测静置时间与上述纳米流体特性变化的关连性。经由长时间检测纳米流体中颗粒的沉降及悬浮性变化,以验证此真空电弧纳米流体合成系统在所不同的制程参数条件下,所产出纳米流体的悬浮稳定性。     

煤系微细高岭石颗粒沉降曳力系数的研究

经模拟和试验研究了煤系微细高岭石颗粒的沉降终端速度;运用应用统计学对煤系微细高岭石颗粒形貌属性进行了统计分析和定义;基于颗粒的形貌特性,修正了颗粒的三维球形因子(Φ)和二维球形因子(X),并构建介观高岭石沉降曳力系数模型Cd-Φ和微观高岭石沉降曳力系数模型Cd-X;运用计算流体力学-离散元法(CFD-DEM)耦合的方法...     

稀疏两相流中颗粒非恒定运动的积分变换分析

首先探讨了线性化后的稀疏颗粒非恒定运动方程的数理性质,然后采用积分变换方法对该方程进行解析,得到了颗粒速度与流体速度间的相互关系．在此基础上分析了颗粒物理性质对其运动特性的影响,并通过计算典型流场中颗粒的运动,进一步定量地显示出颗粒运动随流场结构、颗粒密度和粒径变化的规律．     

水涡轮机械中球形刚性小颗粒的运动

本文对球形刚性小颗粒在任意流场中的受力进行了分析,并根据对称方程,得到了小球在任意流场中的运动方程,为水涡轮机械中固液两相流动的理论研究奠定了理论基础。     

悬浮在向列相液晶中带电胶粒引起的指向矢形变

研究悬浮在向列相液晶中带电胶粘引起的指向矢形变．假定胶粒是球形的,并且表 面电荷在球形颗粒上的分布是均匀的,球形颗粒使指向矢沿径向弱锚泊排列．我们得到了 指向矢形变的解析表示式,它是Ｋｕｋｓｅｎｏｋ等人所提出公式的推广、指向矢形变依赖于两 项衰减,它们分别正比于离开颗粒距离的ｒ２和ｒ３．     

基于圆柱形纳米颗粒的纳米流体导热特性模拟

纳米流体是将纳米颗粒分散在基液形成的一种介质,具有较强的导热性能,在诸多领域具有重要的应用。纳米流体的悬浮颗粒多为球形颗粒,而在实际应用中很多颗粒为非球形。基于平衡态分子动力学模拟方法,研究了含有圆柱形纳米颗粒的纳米流体导热性能。计算结果表明,随着纳米颗粒球形度降低,纳米流体的热导率明显增大。基于纳米流体径向分布函数以及基液和纳米颗粒扩散系数的分析表明,对于相同体积的纳米颗粒,圆柱形纳米颗粒的比表面积较大,颗粒表面的类固液体层效应是非球形纳米颗粒提高纳米流体热导率的主导机制,并且颗粒的布朗运动有可能削弱此效应。该研究结果为强化纳米流体热导率提供了新的思路。     

煤泥水沉降特性的影响因素分析

基于煤泥水组成及性质,分析了悬浮颗粒大小、矿物泥化性质、ζ电位、颗粒间势能、水质硬度和系统特点对煤泥水沉降特性的影响.研究结果表明:0.010mm的颗粒沉降速度很小,是造成选煤厂"细泥"积聚的主要原因;在煤泥水中,不易泥化的矿物较易沉降,而黏土极易泥化,导致煤泥水难以沉降;矿物ζ电位越小,煤泥水越易沉降;黏土颗粒间始终为斥力作用,颗粒处于分散状态.水质硬度决定了煤泥水的沉降性能,水质硬度越低,煤泥水越难沉降.     

絮凝过程絮体粒度分布特征及流场仿真

絮凝主要用以改变水中悬浮颗粒的粒度分布.絮凝反应设备创造的水力条件直接影响其内部三维流场的分布,进而对絮体成长及粒度分布起决定性作用.以聚合氯化铝(PAC)为絮凝剂、水中高岭土悬浮颗粒为去除对象,采用浊度仪、颗粒计数仪等在线仪器对絮凝过程进行实时监测和数据记录,研究改变反应条件对动态絮凝过程絮体粒度分布及絮凝效果的影响,并对絮凝反应器内三维流场进行了仿真计算,有助于改善反应设备水流状态和强化絮凝效果.     

Prediction of coal structure using particle size characteristics of coalbed methane well cuttings

Severely deformed coal seams barely deliver satisfactory gas production. This research was undertaken to develop a new method to predict the positions of deformed coals for a horizontal CBM well. Firstly, the drilling cuttings of different structure coals were collected from a coal mine and compared. In light of the varying cuttings characteristics for different structure coals, the coal structure of the horizontally drilled coal seam was predicted. And the feasibility of this prediction method was discussed. The result shows that exogenetic fractures have an important influence on the deformation of coal seams. The hardness coefficient of coal decreases with the deformation degree in the order of primary structural, cataclastic and fragmented coal. And the expanding-ratio of gas drainage holes and the average particle size of cuttings increase with the increase of the deformation degree. The particle size distribution of coal cuttings for the three types of coals is distinctive from each other. Based on the particle size distribution of cuttings from X-2 well in a coal seam, six sections of fragmented coal which are unsuitable for perforating are predicted. This method may benefit the optimization of perforation and fracturing of a horizontal CBM well in the study area.     

水平井岩屑床层移运动的规律分析

在环空紊流场作用下岩屑床呈具有特定本构关系的浓缩流动介质．本文由岩屑床层移（剪切）运动的内在机理与物理模型出发，研究层移颗粒微观运动的能量平衡与交换，得到了层移床的本构关系和流动速度场方程，以及层移床转静止床的临界水力条件，层移岩屑床的最大厚度，岩屑床的流动能力与流动阻力．阻力方程中考虑了层移床的承压特点及其与环室内外壁的不同摩擦特性．结果表明层移床的结构应力导致其运动失去关于环空几何中心的对称性，流动中心向钻具侧偏移及层移岩屑床的显著增阻效应．     

用SUH算法实现高速流分类

在分析了2种高速流分类算法ABV( aggreg ate bit vector)和 HiCuts( hierarchical intelligent cuttings)的基础上 ,提出了一种新的高速流分类算法 SUH(split united hierarchy) . 通过利用实际的分类器对 SUH进行的测试表明: SUH在占用很小内存的条件下能快速完成预处理和查找过程 ,实现了高速流分类.     

Development of a drill energy utilization index for aiding selection of drill machines in surface mines

Drill machines used in surface mines, particularly in coal, is characterized by a very poor utilization(around 40%) and low availability(around 60%). The main purpose of this study is to develop a drill selection methodology and simultaneously a performance evaluation technique based on drill cuttings produced and drilling rate achieved. In all 28 blast drilled through were investigated. The drilling was accomplished by 5 different drill machines of Ingersoll-Rand and Revathi working in coal mines of Sonepur Bazari(SECL) and Block-II(BCCL). The drills are Rotary and Rotary Percussive type using tricone rock roller bits. Drill cuttings were collected and sieve analysis was done in the laboratory. Using Rosin Ramler Diagram, coarseness index(CI), mean chip size(d), specific-surface area(SSA) and characteristic particle size distribution curves for all the holes drilled were plotted. The predictor equation for drill penetration rate established through multiple regressions was found to have a very good correlation with an index of determination of 0.85. A comparative analysis of particle size distribution curves was used to evaluate the drill efficiency. The suggested approach utilises the area under the curve, after the point of trend reversal and brittleness ratio of the respective bench to arrive at drill energy utilization index(DEUI), for mapping of drill machine to bench. The developed DEUI can aid in selecting or mapping a right machine to right bench for achieving higher penetration rate and utilizations.     

用晶格玻尔兹曼方法研究粒子在脉动压差下的运动

用晶格玻尔兹曼方法模拟脉动流场的形成过程中,发现脉动流场也是一个个的闭合环,但是由于受到入口脉动压差影响,涡流场不是一个完全稳定状态,而是在不断波动变化的.基于最近点法模拟单个粒子在涡流中的运动情况,发现粒子在涡流场中的运动呈现波动的形式,受到入13压强周期性扰动的影响,粒子的水平速度、竖直速度、角速度也呈周期性变化.     

Stochastic formulation of particle kinetics in wall-bounded two-phase flows

This paper presents a generalized framework of stochastic modeling for particle kinetics in wall-bounded flow. We modified a reflected Brownian motion process and straightforwardly obtained a Kramers equation for particle probability density function (PDF). After the wall effects were accounted for as a drift from zero in the mean displacement and suppression in the diffusivity of a particle, an analytical solution was worked out for PDF. Three distinguishable mechanisms were identified to affect the profile of particle probability distribution: external forces, turbophoresis effect, and wall-drift effect. The proposed formulation covers the Huang et al. (2009) model of a wall that produces electrostatic repulsion force and van der Waals force, as well as Monte-Carlo solutions for the Peter and Barenbrug (2002) model under a variety of relaxation times. Moreover, it successfully reproduces the two patterns of particle concentration profiles observed in experiments of sediment-laden open-channel flows. The strength of the wall-drift effect was found to be connected with the interaction frequency between particle and wall. Further exploration of the relationship among flow turbulence, particle inertia, and particle concentration is worthwhile.     

正交射流尾迹气固两相流动的数值模拟

运用气相ｋ－ε湍流模型和颗粒相代数方程模型对正交射流（垂直的交叉射流）尾迹气固两相流动进行了数值模拟，获得了该流动尾迹的气、固相速度分布，颗粒质量流分布，计算结果与实验值定性符合．文中探讨了一次风口（主流入口）粉气质量比对颗粒混合的影响以及颗粒对气相流场的影响，并得到了一些有价值的结论．     

定向喷射钻头的研究和应用

分析了井底岩屑的运移情况,提出优化井底射流,促进岩屑离开井底减少重复破碎从而达到提高钻头机械钻速的目的．由此开发的定向喷射钻头,通过现场使用,达到了设计需求．     

泥石流固相在浆体中沉降规律研究

基于大量试验观察及数据分析研究,揭示了泥石流固相在浆体中的沉降规律。研究影响固相在泥石流浆体中沉降的三个主要因素,分析了各个因素影响泥石流固相沉降的根本原因。泥石流固相在浆体中沉降过程中可分为三个阶段,首先为初始阶段,继而为快速沉降阶段,最后呈减速沉积阶段,并对各个阶段的沉降过程作了详细的分析。其中浆体粘度、固相质量和附加孔隙压力对固相在泥石流浆体中的沉降规律存在着至关重要的影响。     

参数化粒子系统设计及其应用

结合面向对象的分析和设计方法,提出了粒子系统参数化抽象模型的设计方法,该方法针对粒子系统的共有特性,实现了对粒子系统的模块化设计,实现了通用型粒子系统的架构创建.通过OOP实现对粒子属性的封装和继承,使基于OpenGL的粒子系统的设计具有较高的封装和扩展性,并简化了对不同粒子系统的模块化设计和复用,使各种粒子的参数变化易于实现和维护,从而提高了变化粒子系统的设计和实现过程.在实际应用中取得较好的效果.