Analysis of one-dimensional consolidation of soft soils with non-Darcian flow caused by non-Newtonian liquid

Based on non-Darcian flow caused by non-Newtonian liquid, the theory of one-dimensional (1D) consolidation was modified to consider variation in the total vertical stress with depth and time. The finite difference method (FDM) was adopted to obtain numerical solutions for excess pore water pressure and average degree of consolidation. When non-Darcian flow is degenerated into Darcian flow, a comparison between numerical solutions and analytical solutions was made to verify reliability of finite difference solutions. Finally, taking into account the ramp time-dependent loading, consolidation behaviors with non-Darcian flow under various parameters were analyzed. Thus, a comprehensive analysis of 1D consolidation combined with non-Darcian flow caused by non-Newtonian liquid was conducted in this paper.

Pressure Drop of Non-Newtonian Liquid Flow Through Elbows

Experimental data on the pressure drop across different types of elbow for non-Newtonian pseudoplastic liquid flow in laminar condition have been presented. A generalized correlation has been developed for predicting the frictional pressure drop across the elbows in the horizontal plane.

Damped Oscillation of Liquid Column in Vertical U-Tube for Newtonian and non-Newtonian Liquids

在垂直U试管的牛顿的液体的抑制摆动是众所周知的现象和这个液体运动的答案之一因为然而，在圆形的管子中的 laminar 流动政体一般来说被解决，就算由这个答案的 oscillational 运动的时期将近与试验性的结果的被与一致，有由解决的方程的时间的差错的抑制 oscillational 过程的评价不与试验性的结果的一致。因此为牛顿、非牛顿的液体在圆形的 U 试管在 oscillational 运动的速度分布的试验性的结果之上基于， Bingham 塑料流动的速度分发被假定。在直径 D=10mm， 20mm 和 40mm 的垂直 U 试管的免费表面的垂直掉落并且升起的速度的抑制摆动并且也的答案与为牛顿的液体的水和水甘油答案和非牛顿的液体的丙烯酸的共聚物解决方案相比。由新流动模型的这些解决的方程的比较在对试验性的结果的好同意被显示出。上述说的结果详细被描述。

Spray Atomization and Structure of Supersonic Liquid Jet with Various Viscosities of Non-Newtonian Fluids

These experimental investigations are designed to study shock wave characteristics and spray structure. Supersonic liq- uid jets injected into ambient fields are empirically studied using projectile impacts in a two-stage light gas gun. This study looks primarily at the design of the nozzle assembly, the tip velocity of the high speed jet, the structure of the spray jet and the shock wave generation process. The supersonic liquid jets were visualized using an ultra high-speed camera and the schlieren system for visualization to quantitatively analyze the shock wave angle. The experimental re- sults with straight cone nozzle types and various non-Newtonian fluid viscosities are presented in this paper. The effects of nozzle geometry on the jet behavior are described. The characteristics of the shock wave generation and spray jet structure were found to be significantly related to the nozzle geometry. The expansion gases accelerated the projectile, which had a mass of 6 grams, from 250 m/s. As a result, it was found that the maximum jet velocity appeared in the liquid jet with high viscosity properties. Supersonic liquid jets, which occurred at the leading edge the shock waves and the compression waves in front of the jets, were observed. Also, the shock waves significantly affected the atomization process for each spray droplet.

SOLUTION FOR THE OSCILLATION OF A NEWTONIAN FLUID IN A CO-AXIAL VISCOMETER

When one cup of a co-axial viscometer oscillates, the measured moment on the another (stationary) cup shows a phase lag, partly due to the inertial effect of the fluid within the gap between the two cups. Such an effect was illustrated by a new exact solution of Navier-Stokes equation, which was derived herein by a scheme of reducing it to a two-point boundary value problem for ordinary differential equations. The numerical results indicate that, as the Womersley number or the dimensionless gap width increases, the fluid velocity profile within the gap gradually deviates from the linear one and transits to that of the boundary layer type, with the result that the moment decreases in the magnitude and lags behind in the phase. With the advantage of high accuracy and excellent stability, the scheme proposed here can be easily extended to solve other linear periodic problems.

ANALYTICAL SOLUTIONS OF THE HELICAL FLOW OF NONNEWTONIAN FLUID IN ECCENTRIC ANNULAR SPACE

Many problems in petroleum and chemical industry can be reduced to the solution of the helical flow of non-Newtonian fluid in eccentric annular space. The laminar helical flows of the power law fluid and Bingham fluid in eccentric annular space were studied. An approximate analytical solution was obtained by the infinite subdivision method, namely, the eccentric flow was replaced by the infinite concentric flows. Then, the expressions for apparent viscosity distribution, velocity distribution and the flow rate were derived for the power law fluid and the Bingham fluid respectively. In addition, the expressions for pressure drop and stability parameter were also given. It is concluded that this method is much easier to use and more accurate than the method which solves the equations directly. The results are useful for the drilling technology of oil industry, etc.

New conception in continuum theory of constitutive equation for anisotropic crystalline polymer liquids

A new continuum theory of the constitutive equation of co-rotational derivative type is developed for anisotropic viscoelastic fluid—liquid crystalline (LC) polymers. A new concept of simple anisotropic fluid is introduced. On the basis of principles of anisotropic simple fluid, stress behaviour is described by velocity gradient tensor and spin tensor instead of the velocity gradient tensor in the classic Leslie—Ericksen continuum theory. Analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equ- ation of co-rotational type is established for the fluid. A special term of high order in the equation is introduced by author to describe the sp- ecial change of the normal stress differences which is considered as a result of director tumbling by Larson et al. Analyzing the experimental results by Larson et al., a principle of Non- oscillatory normal stress is introduced which leads to simplification of the problem with relaxation times. The special behaviour of non- symmetry of the shear stress is predicted by using the present model for LC polymer liquids. Two shear stresses in shear flow of LC polymer liquids may lead to vortex and rotation flow, i.e. director tumbling in the flow. The first and second normal stress differences are calculated by the model special behaviour of which is in agree- ment with experiments. In the research, the com- putational symbolic manipulation such as computer software Maple is used. For the anisotropic viscoelastic fluid the constitutive equation theory is of important fundamental significance.

Investigation on Liquid Holdup in Vertical Zero Net-Liquid Flow

Zero net-liquid flow (ZNLF) is a special case of upward gas-liquid two-phase flow. It is a phenomenon observed as a gas-liquid mixture flows in a conduit but the net liquid flow rate is zero. Investigation on the liquid holdup of ZNLF is conducted in a vertical ten-meter tube with diameter of 76 mm, both for Newtonian and non Newtonian fluids. The gas phase is air. The Newtonian fluid is water and the non-Newtonian fluids are water-based guar gel solutions. The correlations developed for predicting liquid holdup on the basis of Lockhart-Martinelli parameter are not suitable to ZNLF. A constitutive correlation for the liquid holdup of vertical ZNLF was put forward by using the mass balance. It is found that the liquid holdup in ZNLF is dependent on both the gas flow rate and the flow distribution coefficient.

非牛顿流体气泡羽流涡特性数值模拟研究

为进一步探究非牛顿流体中气液两相流流动特性规律,采用大涡模拟方法(LES)对非牛顿流体气泡羽流的涡特性进行研究。以清水和不同质量分数的羧甲基纤维素钠(CMC)水溶液为研究对象,分析不同表观气速和液相流变特性下气体的运动速度、羽流结构、涡量及涡的演变规律。研究结果表明,涡的演变速率随非牛顿流体浓度的增加而减小。结合Q判据分析不同工况下涡特性分布,随着CMC水溶液浓度的增加流场中的Q值不断降低,且流场内涡的演变速率随着非牛顿流体特性的增加而减弱。

岩土工程不良地质注浆技术研究进展

注浆可有效降低富水环境下岩土介质的透水性,大幅提高岩土结构的强度和刚度。“一带一路”新时代背景下,注浆技术在如火如荼的工程建设中发挥重要作用,有力推动了土木、水利等基础设施的建设进展。本文从非牛顿流体扩散机理、分形几何和劈裂扩散规律方面,对注浆理论研究进行了阐释述评,然后从复合/超细水泥、硅铝酸盐地聚物和微生物菌液方面对注浆新材料性能及工程应用进行了探讨分析,最后对大功率钻探技术、智能灌浆设备进行了梳理总结。注浆技术在建筑、地铁、矿山等领域的应用,必将全面提升岩土工程等项目建设的质量和效益。

基于相场法对非牛顿流体中气泡聚并行为特性的仿真分析

气液两相流因稳定性好被广泛应用于化工生产的各个领域,其中气泡的聚并行为对气泡的大小、形状及运动有显著影响,这些参数直接影响如生物反应器、鼓泡塔等化工设备的相间传质传热过程和工艺性能。使用相场法通过仿真软件对非牛顿流体中的气泡聚并行为进行讨论,分别以气泡在对称分布、偏左分布或偏右分布三种相对位置情况下从竖直气泡、水平气泡和随机气泡三个方面分析对比了气泡的位置和分布对其聚并行为的影响。结果表明,在非牛顿流体中,气泡的相对距离和流体的流动特性都是气泡聚并能否发生的关键因素,它们在气泡处于不同的分布情况下表现出不同的作用规律;另外气泡在不同分布的情况下,其运动规律也表现为不同的特点。

水滴撞击非牛顿除冰液液膜动力学行为特性数值研究

冻雨天气下,过冷大水滴撞击到除冰液液膜后会发生溅射、铺展、互溶等物理过程,除冰液液膜温度降低、浓度下降,液膜冰点上升、黏度下降,引发液膜滑落脱离,大幅缩短防冰保持时间。本文针对冻雨天气下飞机除冰液液膜失效行为开展数值研究,基于流体体积法,并结合组分输运方程,构建了多相、多组分、多体系、多场耦合的水滴撞击非牛顿除冰液液膜的动力学行为模型。基于该数值模型,研究了水滴撞击非稳态过程的动力学行为以及液膜的稀释、降粘等非牛顿流变特性。研究表明:液膜初始浓度越高,对水滴液冠生长抑制程度越大,撞击后水滴的铺展直径越小,水滴和除冰液液膜的碰撞区域的水分输运迁移现象越明显,除冰液液膜在剪切稀释和浓度降低的耦合作用下,黏度下降幅度越明显;水滴初始直径越大,水滴对液膜的作用范围越大,液膜黏度下降幅度越大;水滴的下落撞击速度越大,水滴在液膜内组分迁移速度越快,液膜黏度损耗越明显。

非牛顿液体流变模式的研究

对国内外常用的几种流变模式进行了分析和评价，指出了它们的特点和不足之处。在总结和归纳的基础上，提出了一个带静切应力的三参数多项幂律模式（简称Ｌ—Ｍ模式）。研究还从该模式的本构方程出发，推导出流变参数及有关水力参数计算式，并应用大量的泥浆及水泥浆试验资料和计算数据，对比和分析了各流变模式的适应范围及精确程度，进而证明了Ｌ—Ｍ、Ｈ—Ｂ流变模式具有适应范围广、准确性高的特点。

聚氨酯乳液的的合成及流变性能

The polyurethane emulsion was prepared by introducing carboxylic groups into urethane chains, and its rheology was investigated with rotation viscosimeter. The results of rheology showed that the polyether-urethanc emulsion exhibited the character of Newtonian liquid. The viscosity and stability of the polyurethane emulsion depended on the temperature and carboxylic group content.

超声波气升式内环流反应器传质性能的实验研究

研究了超声波对气升式内循环反应器传质性能的促进作用,重点考察比较了牛顿型流体和非牛顿型流体 有、无超声波时气升式反应器的传质性能及气速、液体粘度、超声功率对总体积传质系数KLa的影响。实验证明， 无论是牛顿型流体还是非牛顿型流体，气速越小，超声功率对总体积传质系数KLa的相对影响越大；随着气速的 增大，这种影响逐渐减小，当气速增大到0.0615m·s-1时，超声波对总体积传质系数KLa的相对影响已较微弱。气 速增加，牛顿型流体和非牛顿型流体的KLa均增加，但牛顿型流体增加的幅度比非牛顿型流体要大。粘度增加，KLa 减小。气速、粘度、超声功率对KLa的影响分别是气速大于粘度大于超声功率。提出了相应的KLa经验关联式，并作了 讨论。

带有内外组合桨的搅拌设备内流场的数值研究

利用滑移网格法计算了以一定转速比反向旋转的内外组合桨搅拌的搅拌设备内的流场,工作介质分别选取98%甘油和1.5%(wt)CMC水溶液。通过对单桨与内外组合桨产生的流场进行对比,研究了搅拌设备内不同高度处速度、速度变化率、表观粘度及剪切速率的分布特点。结果表明:采用内外组合桨,介质为中粘牛顿流体时,在罐内主体区远离罐壁区域径向速度受到一定削弱,但在某些局部区域被增强,而对于假塑性流体径向速度总体上得到增强。采用内外组合桨可以加强轴向循环,改善搅拌设备近壁区的流动状况,且对假塑性流体流动状况的改善要优于中粘牛顿流体,另外还可以显著地提高搅拌设备内的剪切速率,同时使剪切速率的分布比较均匀。

水/甲醇和柴油乳化液的黏度特性实验研究

为研究水/甲醇和柴油乳化液的流变特性与黏度,实验采用了Span80和Tween60配制的3种复合乳化剂Y01、Y02和Y03,它们的HLB值分别为5.36、4.83和4.51.Y03为牛顿流体,动力黏度约为1.5Pa·s.在高剪切速率下,Y01与Y02近似为牛顿流体,动力黏度分别为Y03的88%和92%.乳化液中水相(水与甲醇)总量为10%～50%,乳化剂含量0.8%～8%,动力黏度约在0.003Pa·s到0.02Pa·s之间,为牛顿流体.实验结果表明,如果其它条件不变,乳化液黏度变化规律为:乳化剂HLB值的不同对乳化剂黏度有较大影响;乳化剂含量对乳化液黏度有显著影响,特别当水相含量高于40%时,影响特别显著;提高水相含量(不超过50%),乳化液黏度上升,当水相含量超过40%时,乳化剂含量低于2%和高于4%对乳化液的黏度影响规律明显不同;水相中水与甲醇的比例变化时,对乳化液的黏度影响比较复杂.用乳化液相间界面特征和HLB特征可以从理论上解释上述现象.

影响弹流润滑偏离经典弹流润滑理论的三种因素

详述了在高速、重载和大滑滚比下, 影响弹流润滑偏离经典弹流润滑理论的三个因素, 即温度效应、润滑剂的非牛顿效应和表面粗糙度效应, 并指出了今后的发展方向。

超细Co-Ni合金复合磁流变液的制备及流变性质研究

利用多元醇软化学方法制备了 Ｃｏ－ Ｎｉ超细颗粒，将Ｃｏ－Ｎｉ磁性颗粒与微孔材料通过粘结剂混合研磨，制得复合磁性颗粒，为了克服磁流变液的沉降稳定性，令复合磁性颗粒的密度等于载液的密度，各组分按此比例制备的ＭＲＦ具有较好的稳定性。利用旋转粘度计测试表明，无外场时，磁流变液的剪切应力τ剪切速率γ变化的本构关系为：τ＝１１．４γ０．７，为一非牛顿液体。探讨了剪切应力和表观粘度系数随外加磁场的变化关系，表明研制的ＭＲＦ的流变性质具有较高的低磁场敏感性质。