Influence of the Viscosity of Filled Epoxy Resins on Their Spreading on a Horizontal Surface

The rheological properties of ÉD20epoxyresinbased compositions filled (10–50 vol.%) with quartz sand, quartz flour, or their mixture have been investigated on Reotest2 and RV8 rotational viscosimeters. The relative viscosity of the filled compositions increased with their free volume according to the exponential equation with an exponent of 2.6. The compositions began to show an anomaly of viscosity in flowing for a content of the filler of more than 40 vol.%; the yield stress appeared for 50 vol.%. The rate of spreading of the compositions on a horizontal surface decreased with increase in the composition viscosity according to the exponential equation with an exponent of 1/8, which is similar to that calculated theoretically. The experiments conducted allowed calculation of the formula of epoxybased, selfleveling pouring floors.     

Gravity Effect on the Axisymmetric Drop Spreading

The flattening (spreading) of the axisymmetrical drop on a plane horizontal surface under action of gravity force at zero tangential force (no shear at the gas–liquid interface) is investigated analytically and numerically. We determine the exact profile of compressed drop assuming the condition of drop volume conservation. 2D time dependant numerical model, based on a finite difference method, has been developed to describe the hydrodynamics inside the drop. The energy and Navier–Stokes equations are solved within the drop’s analytical profile. Effects of surface tension and thermocapillarity are taken into account. The effect of gravity has been studied to define main features of the drop dynamics. In calculations vector of gravitational acceleration is oriented perpendicularly to the surface, the Bond number is changed in the range from Bo = 0 to Bo = 151.6. Our results show that the gravity has a significant effect on the drop spreading.     

SE电池电极制造过程中的硅片表面粗糙度对蜡滴铺展的影响

建立了蜡滴铺展系数与多晶硅片表面粗糙度的准则关系式,运用最小二乘法数据拟合方法得出了蜡滴铺展系数与相关参数的实验关系式。该实验关系式揭示了喷蜡蜡滴在多晶硅片上的铺展直径与多晶硅片表面粗糙度间的函数关系。     

Measurement of the Viscosity of a Liquid at High Pressures

A method of measuring the viscosity of a liquid over a wide range of pressures and temperatures and a rotation-type viscosimeter which employs this method are proposed. The possibility of determining and automatically regulating the flow of a liquid using the results of measurements of the viscosity in real time by employing two viscosimeters, placed in different sections of the channels, is pointed out. __________ Translated from Izmeritel'naya Tekhnika, No. 10, pp. 51–53, October, 2005.     

Spreading of a Liquid Droplet over a Solid Horizontal Surface

A study is made of the kinetics of flow of the finite volume of an electrorheological liquid on a horizontal substrate.     

Prediction of the Viscosity of Liquid Mixtures

This paper describes the application of the theoretically based scheme of Vesovic and Wakeham, modified by making use of the hard-sphere model of Dymond and Assael, to the prediction of the viscosity of liquid mixtures. The purpose of the paper is to examine this scheme in more detail than earlier to find out in what circumstances it works well and when it fails. Hence, the scheme is employed to predict, for the first time, the viscosity of a wide range of mixtures of quite disparate liquids from groups of hydrocarbons, through combinations of alcohols and hydrocarbons, to halogenated refrigerants. It is shown that, in all cases, provided that the mass ratio of the pure components is close to unity, the predictions show excellent agreement with experiment.     

Influence of Heterogeneous Plates on the Axisymmetrical Oscillations of a Cylindrical Drop

Natural and forced oscillations of a sandwiched fluid drop are investigated. In equilibrium, the drop is in the form of a cylinder. It is surrounded by another liquid and bounded axially by two parallel solid planes. The Hocking boundary conditions hold on the contact line: the velocity of the contact line motion is proportional to the deviation of the contact angle from its equilibrium value. In this case, the Hocking parameter (the so-called wetting parameter) is the proportionality coefficient. This parameter is considered as a function of coordinates, i.e. solid plates have a nonuniform surface. The axisymmetrical vibration force is parallel to the symmetry axis of the drop. The solution of the boundary value problem is found using the Fourier series of Fourier series expansion of the Laplace operator in eigenfunctions. Both the axisymmetrical mode and different azimuthal modes are excited because energy is transferred from the axisymmetrical modes to other modes due to nonuniform surfaces.     

The Effect of Liquid Viscosity on the Formation of Thermocapillary Structures

An experimental study of the formation of thermocapillary structures at low Reynolds numbers and temperature gradients at the surface of the film in a wide range of the liquid viscosity is performed. The data on the distance between the jets are generalized. It is demonstrated that the transverse dimension of the structures is determined by the capillary constant and does not depend on either the liquid viscosity or the flow rate (Reynolds number of the film).     

The Viscosity of Organic Liquid Mixtures

The paper reports measurements of the viscosity and density of two heavy hydrocarbon mixtures, Dutrex and Arab Light Flashed Distillate (ALFD), and of their mixtures with hydrogen. The measurements have been carried out with a vibrating-wire device over a range of temperatures from 399 to 547 K and at pressures up to 20 MPa. Measurements have also been carried out on systems in which hydrogen at different concentrations has been dissolved in the liquids. The measurements have an estimated uncertainty of ±5% for viscosity and ±2% for density and represent the first results on these prototypical heavy hydrocarbons. The results reveal that the addition of hydrogen reduces both the density and viscosity of the original hydrocarbon mixture at a particular temperature and pressure.Paper presented at the Seventh Asian Thermophysical Properties Conference, August 23–28, 2004, Hefei and Huangshan, Anhui, P. R. China.     

Molecular Dynamics Calculation of the Viscosity of Xenon Gas

The density variation of the viscosity of xenon gas is determined using molecular dynamics simulation with a semi-empirical pair potential fit to low-density gas properties. The gas states ranged in density from 0.37 to 7.62 mol · dm⁻³, and varied in temperature from 240 −591 K. The simulation results match the kinetic-theory predictions for the model potential at the lowest density, and systematically lie below the experimental values for higher densities. This indicates the need for many-body interactions to accurately predict the viscosity of xenon gas at even moderate densities. An operational criterion for identifying the density region where kinetic theory is appropriate is proposed.     

单音片振动式液体粘度测量仪的研究

论述了单音片传感器测量液体粘度的原理及结构特点，它是利用压电陶瓷的自激振动激励单音片在液体中振动，从而测得液体粘度，仪器同时配有温度传感器，可测得实时温度，该传感器与计算机配合使用时，即可成为一种高精度的液感器，可测得实时温度，该传感 器与计算机配合使用时，即可成为一种高精度的液感器，可测得实时温度，该传感器与计算机配合使用时，即可成为一种高精度的液体粘度测量仪器，文中对仪器的测量数据进行了分析，这种仪器具有响应速度快、精度高、使用方便等特点，可广泛用于石油、化工、仪器等领域。     

乐甫波的液体粘度传感研究

利用部分波理论和边界条件精确推导,对“粘性液体/非压电薄膜/压电基底”3层乐甫波结构建模,分析得出随叉指周期变小,液体粘度灵敏度提高,传播衰减增大;随“薄膜厚度与波长之比”增大,液体的粘度灵敏度随之先减小再增大,液体密度灵敏度几乎为零。优化设计了以36°钽酸锂和SiO₂为基底和薄膜的乐甫波器件,制作并测试实物,实验结果与数值仿真基本一致,表明了理论模型的正确性。     

油墨黏度对胶印印刷质量的影响

通过分析胶印油墨黏度特性以及胶印过程剪切速率状态,并通过实验室测量油墨黏度,获得了油墨由橡皮滚筒向纸张转移过程的黏度。 然后配比不同黏度的油墨上机印刷,得到了油墨黏度和印刷品实地密度、网点增大以及色度之间的关系,分析了油墨黏度对印刷质量参数影响的机理,为企业合理使用去黏剂提供依据。     

Characteristics of the Aerosol Cloud Formed during Microexplosive Fragmentation of a Two-Component Liquid Drop

Technical Physics Letters - Results of experimental investigation of the formation of aerosol cloud during explosive fragmentation of two-component (water–rapeseed oil) liquid drops intensely...     

Sliding Dynamics of the Wigner Crystal on Liquid He

The Wigner crystal on liquid He accompanies with periodic corrugation of the He surface; dimples. The dynamics of the crystal is coupled with the motion and the deformation of the dimples. Nonlinear phenomena found in AC Corbino conductivity are attributed to the collective sliding of the electrons out of the dimples. In order to inspect the dynamical transition to the sliding state, we have developed a novel experimental method using a so-called t² pulse, whose leading and trailing edges change in proportion to the square of time; V t². Since the force exerting upon the crystal is proportional to the time derivative of the input voltage, dv/dt, the t²-pulsed method is expected to realize a continuous sweep of the driving force, resulting in the real-time observation of the sliding transition. The observed response shows clearly the sliding, revealing that the external force to the crystal determines the sliding transition.     

Density of Liquid Ni-Mo Alloys Measured by a Modified Sessile Drop Method

The density of liquid binary Ni-Mo alloys with molybdenum concentration from 0 to 20% (mass fraction) wasmeasured by a modified sessile drop method. It has been found that the density of the liquid Ni-Mo alloys decreaseswith increasing temperature, but increases with the increase of molybdenum concentration in the alloys. The molarvolume of liquid Ni-Mo binary alloys increases with the increase of temperature and molybdenum concentration. Thepartial molar volume of molybdenum in Ni-Mo binary alloy has been approximately calculated as [13.18-2.65×10~(-3)T+(-47.94+3.10×10~(-2)T)×10~(-2)X_(Mo)]×10~(-6)m~3·mol~(-1). The molar volume of Ni-Mo alloy determined inthe present work shows a negative deviation from the ideal linear mixing molar volume.     

The Dynamics of Spreading of Oils on Hydrophilic and Hydrophobic Surfaces Revisited Using Computational Fluid Dynamics

The dynamics of drop spreading on horizontal smooth surfaces of different wettabilities is revisited using computational fluid dynamics （CFD）. For this purpose, a recently developed CFD model, based on the volume of fluid technique （VOF）, with piecewise linear interface calculations method （PLIC） for interface reconstruction, is generalized and applied to simulate the time evolution of spreading drops on solid surfaces （drop base radius and dynamic contact angle）. The CFD simulations are quantitatively compared with previously published experimental results from other research groups. The influence of different factors, such as oils nature （silicone, mineral, peanut and coconut）, viscosity （0.02-1 Pa.s）, drop volume （0.3-38 μL） and type of surfaces （hydrophilic glass, stainless steel and hydrophobic glass） on the temporal evolution of the drop base radius and contact angle is investigated. For hydrophilic surfaces, the predictions of the CFD model agree remarkably well with the measurements. For hydrophobic surfaces, a small deviation between calculated and experimental results occurs because the model does not consider the partial slippage which can take place on hydrophobic materials. Despite neglecting this aspect, the simulations are found to capture the key features of drop spreading on hydrophobic surface. The fact that we obtain a good agreement between the proposed theory and the experimental results for a large range of oils and surfaces over five decades of time is a strong argument in favor of the model. The accuracy of the model demonstrates also that the influence of the surface wettabity （partial wetting and complete wetting） can be successfully simulated. The numerical results reproduce perfectly the spreading regimes which occur during the time course of the drop. The succession of two different regimes takes place in the following order： a hydrodynamic regime followed by a gravity regime.