智能材料电流变流体在运输包装中的应用研究

在深入分析缓冲运输包装基本理论基础上，并将研制的ERF阻尼器用于缓冲隔振支座的设计中，可实现有效的振动控制，使产品在运输过程中不会由于振劝冲击而损坏，经仿真模拟缓冲隔振效果明显。     

Structure and dynamics of dipolar fluids under strong shear

Molecular dynamical simulation has been carried out to investigate the structure and dynamics of a dipolar fluid under strong shear. Dipolar fluid consists of polarizable particles, which have an induced dipole moment in the applied field direction. Shear stress is perpendicular to the field direction. When shear stress is small, the flow has a flowing-chain structure. If shear stress increases to pass a critical value, flowing-chain structure changes to flowing layer structure. Each layer is parallel to the flow direction and shear direction. Within one layer, particles form strings in the flow direction.     

Electrorheological Fluids Based on Titania Particles Coated with Silica and Their Application in Smart Windows

The electrorheological (ER) fluids are colloidal suspension of highly polarizable particles in a non-conducting solvent.Chains of submicron-sized particles formed along an applied DC electric field by the so-called electrorheological effect.According to the obvious change of transmittance of the ER fluids in a DC electric field when the polarized particles arranged along the field,the model of smart window was proposed by sandwiching the ER fluids based on titania particles coated with silica between a pair of In-Sn oxide (ITO) coated glasses.The solar transmittance change as much as 48.0% was obtained with the wavelength of 500 nm at the maximum on applying and removing the electric field of 500V/mm.     

Universal yield stress function for biocompatible chitosan based-electrorheological fluid: Effect of particle concentration

Electrorheological (ER) response of biocompatible particles suspended in an insulating silicone oil, was investigated under several different applied external electric field strengths. Chitosan, a biodegradable polysaccharide, was used as anhydrous ER materials. The effect of particle volume concentration on their ER response was examined by focusing on the measurement for rheological and electrical properties. The yield stress of chitosan suspended in silicone oil system as a function of applied electric field strength showed different value of slopes for different particle concentrations, however, all data points collapse onto a universal scaling function.     

Effect of ferrous and ferric iron impurities on the crystallization of gypsum and sludge formation in wet-process phosphoric acid

The effect of ferrous and ferric iron on the crystallization of calcium sulfate dihydrate, the rate of filtration, and the precipitation of sludge in concentrated acid were investigated. A bench scale unit was used to simulate dihydrate plant conditions. It was found that ferrous iron was oxidized to ferric, and the behavior of the two impurities in the acid was therefore very similar. At low levels of impurities, ferrous and ferric iron improved filtration, but further additions decreased it. Sludge collected from the concentrated acid after five weeks was mainly calcium sulfate hemihydrate and anhydrate. With the addition on 0.5% and 0.75% iron impurities however, the presence of (Fe,Al) 3 KH 14 (PO 4 ) 8 ·4H 2 O was evident in electron micrographs.     

Preparation of high performance electrorheological fluids with coke-like particles from FCC slurry conversion

The electrorheological fluid (ERF) with coke-like particles from thermal conversion of fluid catalytic cracking (FCC) slurry was prepared and their ER performance was investigated. The results show that an ERF containing these solids is a high performance material with high shear stress, low current density and long-term stability. Shear stress higher than 2 kPa and current density less than 60 μA/cm² was obtained in a 2 kV/mm DC field. The volume fraction of clear liquid released from the ERF was less than 5 vol% after several months of static test, indicating the ERF is stable and meets commercial application requirements. The influence of thermal conversion level and the orientation of condensed aromatics on ERF performance are discussed.     

The influence of solid-phase concentration on the performance of electrorheological fluids in dynamic squeeze flow

The yield stress of electrorheological (ER) fluids increases by orders of magnitude when electric field is applied across them. In the absence of the field, ER fluids behave as Newtonian fluids. This paper is concerned with an experimental investigation to determine the rheological performance of ER fluids, consisting of a dielectric liquid carrier with a range of solid-phase concentration. The ER fluid was contained in a squeeze cell, which during motion subjects the fluid to both compressive and tensile loading. The results were analysed in terms of the capacity for the transmission of imposed forces across the fluid and showed a great dependence on the applied D.C voltage and the weight fraction of the dispersed solid-phase. In addition, the implications of the results to vibration control, where the ER fluid is employed in an engine mount, are discussed.     

温度对电流变体智能材料的性能影响

本文通过化学合成的方法制备了含氯离子(Cl-)的草酸氧钛钡(BTO)颗粒材料,以甲基硅油Ⅰ为基础液,制备了电流变体,考察了该体系的粘度和流变等性能随温度的变化规律。     

Effects of electric field on hydrodynamic characteristics of finite-length ER journal bearings

A numerical analysis is performed on the hydrodynamic characteristics of electrorheological (ER) fluid flows in journal bearings based on computational fluid dynamics (CFD) techniques. The bearing has a finite-length and operates under incompressible laminar flow with steady conditions. The analysis is based on the numerical solution of full three-dimensional Navier–Stokes equations. The applied electric field is imposed partially along a contractive section of the journal bearings and the modified Bingham plastic model is used to describe the behavior of ER fluid. The results presented are obtained by using finite-volume-methods and solved by the semi-implicit method for pressure-linked equations (SIMPLE) algorithm. In this study, cavitation effects are also considered by using the viscosity modeling. The results have shown that the influences of ER effects, caused by the applied electric field, on the journal bearing characteristics are significant and not negligible. Compared with the Newtonian lubricant case, the effects of the ER effects provide an enhancement in the load-carrying capacity, but do have little effects on the attitude angle. The quantitative effects on load-carrying capacity are more pronounced for journal bearings operating at higher values of eccentricity ratio or lower rotary speed.