AN EFFICIENT NUMERICAL MODELING OF THE DC RESISTIVITY LOGGING: THEORY AND APPLICATIONS

The numerical solution of Green's function for the potential in 2-D arbitrary in-homogeneous media with axial symmetry has been given by use of efficient half-analytical, half-numerical hybrid method. Then the logging responses of various kinds of the DC resistivity log with axisymmetric excitation have been obtained by using surface integral equation method to match the boundary conditions on the electrodes of the logging sonde. Comparing the results with that obtained by other methods, one can see good precision and efficiency of the given method. Some applications of the numerical modeling have been also discussed.     

五省(市)环境天然放射性水平调查概况

本文介绍了浙江、辽宁、贵州三省及包头、武汉两市环境天然放射性水平调查方案的制定原则,质量保证措施及主要调查结论。对正在进行或即将开展此类工作的其它省(市),本文也提出了若干可供参考的建议。调查结果表明,三省两市陆地γ辐射剂量率(不包括宇宙射线贡献在内的,天然γ辐射在离地面1m 高处空气中产生的吸收剂量率),以省或市为单位的地区平均值在(5.78～7.23)×10~(-8)Gyh~(-1)之间,五省(市)按面积加汉的平均值为6.49×10(?)Gyh~(-1),按人口加权的平均值为6.44×10~(-8)Gyh~(-1)五省(市)土壤和水体中的天然放射性核素含量,基本上属于正常水平;开采与冶炼伴有放射性钍、铀系核素的矿物,是五省(市)人为活动造成环境放射性活染的主要来源。     

2. Numerical Simulations of Water Flow and Solute Transport Applied to Acid Sulfate Soils

Field investigations of Rassam et al. in 2001 have highlighted the effects of infiltration, drainage, and evapotranspiration on the dynamics of water flow and solute transport in acid sulfate (AS) soils. In this work, HYDRUS-2D is adopted as the modeling tool to elucidate the trends observed in that field experiment. Hypothetical simulations have shown that the relative contribution of drains to lowering the water table is significant only when closely spaced drains are installed in coarse textured soils, evapotranspiration being the main driving force in all other cases. AS soils reaction products that are close to a drain are readily transportable during infiltration and early drainage, but those produced farther away from it near the midpoint between drains are only slowly transported during a prolonged drainage process. Simulating the field trial of Rassam et al. has shown that drain depth and evapotranspiration significantly affect solute fluxes exported to the ecosystem. Managing AS soils should target minimal drain depth and density. Partial or full lining of the drains should be considered as a management option for ameliorating the environmental hazards of AS soils.     

涡旋燃烧炉正反切向进风气固流动的数值模拟

涡旋燃烧炉是最近研制的一种新型固体燃料旋风燃烧炉，它采用了多级切向进风的结构。本文应用气固两相流的多连续介质模型及其数值计算方法，针对分级供入炉内的空气采用正反切向进风的条件，对涡旋燃烧炉内的气固两相湍流旋流流动进行了数值模拟。通过模拟结果的分析及其与分级同向切向进风情况的比较，探讨了在涡旋燃烧炉中采用多级正反切向进风方式的可能性。     

盐穴地下储气库注采热工性能模拟

储气库在建造和运行时，一方面溶腔内气体通过自然对流与周围盐层进行热交换，与周围盐层壁面形成不稳态导热温度场；另一方面连续注采循环，使腔内气体压力、温度发生变化，特别是在连续采气时，降压的焦耳-汤姆逊效应极易使井口气体压力和温度进入生成水化物的危险范围，因此动态确定盐穴储气库注采天然气时的热工特性变化十分必要。为此，根据热力学、传热学和流体力学理论，针对注采过程天然气在井筒流动和溶腔内传热过程的特点，将井筒、溶腔和周围盐层视为一个系统，提出了描述注采动态工程相互耦合的数学模型及其求解方法，并开发了相应的数值计算软件。该软件可预测盐穴地下储气库在连续注采气过程中，溶腔内及井筒顶、底部气体的压力和温度，并判断水化物形成的危险范围等。研究成果能对盐穴地下储气库的建造和技术特性做出预测分析，对其运行工况给予指导，并对注采气地面系统的优化设计提供理论分析依据。     

Research on dynamic micro-deformation under laser point source

The dynamic micro-deformation of the specimen under laser point source is measured using a laser beam reflex amplifier system and numerically simulated by Msc.Marc software. Compared with experimental result and calculated result, the final deformation direction of the specimen depends on the result of the thermal strain and the phase transformation strain cooperation, away from the laser beam or towards the laser beam, the final deformation angle depends on temperature gradient in the thickness direction and the geometry constraint of the specimen. The conclusion lays the foundation for further research on the mechanism of laser bending. At the same time, it is proposed that the model of calculation based on classical Fourier heat transfer theory cannot be enough to simulate the dynamic micro-deformation of the specimen under laser point source, the model of calculation should be modified in the future.     

共注射成型充填过程的运动界面追踪

基于Hele-Shaw流动模型推导出共注射成型充填模拟的数值模型基础上，通过引入厚度分数，采用控制体积法实现了充填过程中多重运动界面的追踪。等温数值模拟结果与MOLDFLOW的模拟结果相吻合，并能正确反映粘度对层厚分布的影响。     

Numerical Analysis of a Tunnel Support Design in Conjunction with Empirical Methods

In this paper, preliminary support design of a tunnel was analyzed by numerical and empirical approaches. The case study for this analysis is a tunnel to be constructed on the Bilecik-Istanbul roadway in Turkey. The rock mass properties of the tunnel route and design support recommendations were obtained by using an empirical approach. The rock mass properties obtained from the empirical method were used as input parameters for the numerical analysis. The empirical and numerical results, in terms of support design, were evaluated. It was seen that the numerical analysis results supported by empirical values were logical and reliable.     

甲醇-柴油混合燃料燃烧的数值模拟

本文根据柴油机燃烧过程的数学模型,将Chemkin中甲醇燃烧动力学反应机理导入Fluent软件中,对各种比例下的甲醇柴油微乳液进行了燃烧模拟计算,并用S195柴油机在台架上对计算值进行测试验证。结果表明:数值模拟的方法可靠。在不改动柴油机结构的情况下,甲醇含量影响燃烧效果,低甲醇含量可以提高燃烧效率,高甲醇含量降低燃烧效率,甲醇含量为10%时最佳。     

Shear resistance in stainless steel plate girders with transverse and longitudinal stiffening

This paper summarizes and presents main results of the investigation conducted in the Department of Construction Engineering of the UPC dealing with shear behaviour of stainless steel plate girders. Initial shear buckling stress together with ultimate shear capacity of these structural elements have been evaluated with special attention paid to the effect of including stiffeners, both transverse and longitudinal. The studies conducted, both numerical and experimental tests, have permitted the development of new and simple design expressions to determine more accurately the initial shear buckling stress in stainless steel web panels and the ultimate capacity of plate girders considering the presence of a rigid or non-rigid end post.