电解质体系变化对初晶温度的影响研究

在分析国内多家企业电解质成分和测定初晶温度的基础上,通过统计分析和拟合计算,分析了电解质成分与初晶温度之间的关系,给出了电解质体系变化对初晶温度的影响规律,并改进了Solheim A和Rolseth S初晶温度经验数模拟合计算公式,提高了计算值与实测值的吻合度。

Characteristic of Drop Coalescence Resting on Liquid-Liquid Interface

The trajectory model of dispersed phase drops and the model of basic flow for drop motion between two inclined parallel plates are derived with the optimized calculation. The analytical results of direct numerical simulation indicate that the basic flow plays an important role in the drop coalescence on liquid-liquid interface. In the stratified two-phase flow field, the smaller droplets are difficult to drain the thin continuous film between the approaching droplets and bulk interfaces and eventually immerse into the trickling film to yield coalescence. They almost attain the velocity of their local surroundings. Moreover, the basic flow exerts a dominant influence on the motion of smaller droplet. The smaller droplets are easily entrained by the basic flow. On the contrary, the larger drop presents advantageous characteristics of coalescence due to its high velocity. The range of 0.3 mm < δR≤ 0.75 mm is the advantageous drop coalescence condition since the rapidly varied velocity and its first derivative theoretically cause the forces acting on a drop to become imbalanced. On the other hand, the thin layer of the continuous phase drained from the interval between the drops and trickling film should not be neglected in the calculation of shearing force since it is important for drop rotation. The drop rotation is an indispensable factor in coalescence.

Numerical simulation of asphalt mixture based on three-dimensional heterogeneous specimen

In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic （where mastic is a kind of fine mixture composed of asphalt binder mixed with fines and fine aggregates） and air voids, based on three-dimensional （3D） heterogeneous specimen, X-ray computerized tomography （X-ray CT） was used to scan the asphalt specimens to obtain the real internal microstrnctures of asphalt mixture. CT images were reconstructed to build up 3D digital specimen, and the viscoelastic properties of mastic were described with Burgers model The uniaxial creep numerical simulations of three different levels of aggregate gradation were conducted. The simulation results agree well with the experimental results. The numerical simulation of asphalt mixture incorporated with real 3D microstructure based on finite element method is a promising application to conduct research of asphalt concrete. Additionally, this method can increase the mechanistic understanding of global viscoelastic properties of asphalt mixtures by linking the real 3D microstructure.

Numerical simulation for influences of pressure solution on T-H-M coupling in aggregate rock

The pressure solution model of granular aggregates was introduced into a FEM code which was developed for the analysis of thermo-hydro-mechanical(T-H-M) coupling in porous medium. Aimed at creating a hypothetical model of nuclear waste disposal in unsaturated quartz aggregate rock mass with laboratory scale, two 4-year computation cases were designed: 1) The porosity and permeability of rock mass are functions of the pressure solution; 2) The porosity and the permeability are constants. Calculation results show that the magnitude and distribution of stresses in the rock mass of these two calculation cases are roughly the same. And, the porosity and the permeability decrease to 43%-54% and 4.4%-9.1% of their original values after case 1 being accomplished; but the negative pore water pressures in cases 1 and 2 are respectively 1.0-1.25 and 1.0-1.1 times of their initial values under the action of nuclear waste. Case 1 exhibits the obvious effect of pressure solution.