AN EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE STARTING FLOW OF A UNIFORMLY ACCELERATING CIRCULAR CYLIINDER

The starting flow around a uniformly accelerated circular cylinder is investigatedby flow visualization techncque and solving N-S equations numerically in detail.The results ofthe starting flow are similar with those of the impulsively started one.At lower Re_α,numbers the“phenomenon a”is revealed;the“phenomenon β”appears at higher Re_α numbers,but withonly one secondary vortex.At the early stage of the starting vortex formation,the flow islaminar;at the later stage,the flow transforms into turbulent flow.The velocity distribution inthe flow field is measured with the multiwires installment.The calculational results are comparedwith the results of experiment,and both are in agreement with each other.     

用小尺寸R－CT试样研究核压力容器钢断裂韧性及与Charpy试样的比较

提出了一种用双边带深侧槽的小尺寸圆形紧凑拉伸试样评定核压力容器（ＲＰＶ）钢断裂韧性的单试作试验方法，给出了用该方法测定的两个厂家生产的核压力容器用Ａ５０８ＣＬ３钢的断裂韧性参数，还与Ｃｈａｒｐｙ试样的试验结果及大尺寸标准试样的试验结果进行了比较。研究结果表明：用双边带深侧槽的小尺寸Ｒ－ＣＴ试样测得的断裂韧性值比相同恻槽深度预制疲劳裂纹Ｃｈａｒｐｙ试样的测试值更接近有效断裂韧性值，所以，用于核压力容器断裂韧性的监测是可行的。     

用试井方法确定注水后地层渗透率的变化

大港油田已进入开发中后期，高含水油田占73％，开发初期的一些参数已不适合现在开发的需要。研究出一套用试井方法确定注水以后地层渗透率变化的方法，对大港油田的增储上产具有重要意义。     

The Role of Metastable Atoms in a Homogeneous Atmospheric Pressure Barrier Discharge in Helium

A one-dimensional fluid model for homogeneous atmospheric pressure barrier discharges in helium is presented by considering elementary processes of excitation and ionization including a metastable atom effect. Using this model we investigate the behaviours of the helium metastable atoms in discharges as well as their influence on the discharge characteristics. It is shown that the metastable atoms with a relatively high concentration during the discharge are mainly produced in the active phase of the discharge and dissolved in the off phase. It is also found that the metastable atom collisions can not only provide seed electrons for discharges but also influence the concentration of ions. A reduction of matestable atom density results in a drop in the charged particle densities and causes a qualitative change in the discharge patterns.     

压裂泵往复密封性能及机理研究

根据流体动压润滑理论，对压裂泵柱塞密封摩擦副的润滑机理进行了理论分析。在排出和吸入行程，柱塞密封摩擦副均能满足流体动压润滑的条件，即在柱塞与密封界面上能形成并保持一定厚度的油膜润滑密封，从而达到减小摩擦提高寿命的目的；建立了摩擦界面油膜厚度和泄漏量的计算公式。利用有限元法理论，对密封圈的压力沿轴向的分布规律、泄漏量与压力变化关系进行了模拟计算。对往复密封圈沿轴向压力分布、泄漏量随压力变化进行了测试；试验结果表明，建立的计算模型具有较高的计算精度，揭示了压裂泵的密封机理。     

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.     

Evaporation and Evolution of Suspended Solution Droplets at Atmospheric and Reduced Pressures

Thermal history and solute precipitation behavior of suspended solution droplets of sodium chloride (NaCl), magnesium sulphate (MgSO₄), and zirconium hydroxychloride (ZrO(OH)Cl) evaporating at atmospheric and reduced pressures are studied. Experimental measurements on the variation of droplet diameter, solution concentration, and temperature during the evaporation period are presented and discussed. The results of solute precipitation behavior in solution droplets observed under an optical microscope are displayed and discussed. Results indicate that reducing the pressure (∼ 33 kPa) results in a change in the solution droplet evaporation rate, but the thermal histories of a particular solution droplet are similar at the atmospheric and reduced pressures. At atmospheric and reduced pressures used in this study, the d² law for solution droplets is valid at early stages of the evaporation and before the solute precipitation initiates. Drying of MgSO₄ and ZrO(OH)Cl solution droplets results in the formation of spherical particles, whereas drying of spherical NaCl solution droplets results in the formation of cubic particles.     

热流量计的原理

根据工业及家庭供暖的要求，设计并研制成一种新型的热流量计，它采用方便而新颖的采集信息方式，并使用CPU精确实时的进行控制和运算，保证了热流量计的精确、实时和“分户计量”。     

p,V, T and derived thermodynamic data for toluene,trichloromethane, dichloromethane,acetonitrile, aniline,and n-dodecane

Experimentally determined p,V,T data are reported for toluene, trichloromethane, dichloromethane, acetonitrile, aniline, and n-dodecane at 278, 288, 298, 313, and 323 K, except for dichloromethane, for which the highest temperature was 298 K. At each temperature, measurements were done at pressures up to about 280 MPa or (for aniline and n-dodecane) at a lower pressure slightly below the freezing pressure at the temperature of measurement. Values of the isobaric expansivity isothermal compressibility and (for toluene, trichloromethane, dichloromethane, and acetonitrile) internal pressure, derived from the p,V,T data, are presented.     

西北江三角洲来水来沙的非线性分形特征

根据西、北江干流高要、石角及西北江三角洲网河区顶点马口、三水四个水文站的流量和含沙量资料 ,应用非线性分形原理的R S方法 ,计算西北江干流及西北江网河区顶点四个水文站的流量、含沙量的赫斯特数H和分形维数D ;探讨西、北江干流来水来沙的分形特征及西北江三角洲的分水分沙规律。结果表明 ,流量的分维数略大于含沙量的分维数 ,三水站流量及含沙量的分维数与其上游的石角站流量、含沙量的分维数相差较大 ,与思贤的分水分沙造成西北江的水沙交换有关