Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations

This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC^3D geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO₂ Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO₂ storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC^3D for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.     

ANSYS在工科材料力学教学中的应用

探讨了ANSYS软件应用于材料力学教学中的优势,重点讨论了将ANSYS的屈曲分析应用到材料力学压杆稳定教学中,将原本抽象的欧拉公式理论教学变得形象生动。并利用ANSYS仿真技术来模拟压杆失稳的屈曲过程,弥补了实验不足的缺点。     

多媒体技术在“工程力学”教学改革中的应用

适应社会对应用型人才的需要,改变传统"工程力学"教学中存在的弊端,应用现代多媒体技术,加快应用型人才培养的步伐,从而缩短理论与实践的距离。     

The mechanical behaviour of coal with respect to CO2 sequestration in deep coal seams

Carbon dioxide displays a strong affinity for coal due to its propensity to adsorb to the coal surface. The process of CO₂ adsorption on coal causes lowering of surface energy and, it is hypothesised that an associated decrease in surface film confinement results in a decrease in material tensile resistance. Following the results of work carried out on the mechanical influence of CO₂ on brown coal under in situ conditions [Viete DR, Ranjith PG. The effect of CO₂ on the geomechanical and permeability behaviour of brown coal: implications for coal seam CO₂ sequestration. Int J Coal Geol 2006;66(3):204–16], a theoretical explanation is proposed for the perceived lack of a weakening effect with the adsorption of CO₂ to coal at significant confining pressures. We propose that at significant hydrostatic stresses, resistance to failure is otherwise provided (by external confinement) and the effects of adsorptive weakening are concealed. Our model predicts that adsorptive weakening, fracturing under in situ stresses, and associated permeability increases are not an issue for coal seam CO₂ sequestration for sufficiently deep target seams. Lowering of the elastic modulus of coal upon introduction of CO₂ may proceed by means other than surface energy lowering and could well occur irrespective of the depth of sequestration. The effect of elastic modulus lowering under in situ conditions would be beneficial for the long-term retention of sequestered gases.     

Modeling And Performance Evaluation Of Branch And Value Prediction In Ilp Processors

Speculative execution is one of the key issues to boost the performance of future generation microprocessors. In this paper, we introduce a novel approach to evaluate the effects of branch and value prediction, which allow the processor to execute instructions beyond the limits of control and true data dependences. Until now, almost all the estimations of their performance potential under different scenarios have been obtained using trace-driven or execution-driven simulation. Occasionally, some simple deterministic models have been used. We employ an analytical model based on recently introduced Fluid Stochastic Petri Nets (FSPNs) in order to capture the dynamic behavior of an ILP processor with aggressive use of prediction techniques and speculative execution. Here we define the FSPN model, derive the state equations for the underlying stochastic process and present performance evaluation results to illustrate its usage in deriving measures of interest. Our implementation-independent stochastic modeling framework reveals considerable potential for further research in this area using numerical solution of systems of partial differential equations and/or discrete-event simulation of FSPN models.     

NUMERICAL SIMULATION OF PROPAGATION AND BREAKING PROCESSES OF A FOCUSED WAVES GROUP

A two-dimensional numerical wave flume is developed to study the focused waves group propagation and the consequent breaking processes. The numerical model is based on the Reynolds-Averaged Navier-Stokes (RANS) equations, with the standard k-ε turbulence model to simulate the turbulence effects. To track the complicated and broken free-surface, the Volume Of Fluid (VOF) method is employed. The numerical model combines the "Partial Cell Treatment (PCT)" method with the "Locally Relative Stationary (LRS)" concept to treat the moving wave paddle so that various waves can be generated directly in a fixed Cartesian grid system. The theoretical results of the linear and nonlinear waves are used to validate the numerical wave flume firstly, and then a plunging breaking wave created by a focused waves group is simulated. The numerical results are compared to the experimental data and other simulation results, with very good agreements. The turbulence intensity, the flow field and the energy dissipation in the breaking processes are analyzed based on the numerical results. It is shown that the present numerical model is efficient and accurate for studying the waves group generation, the waves packet propagation, and the wave breaking processes.     

催化裂化柴油各馏分段碱性氮及总硫含量分布研究

对多家炼厂的催化裂化（FCC）柴油采用按体积切割馏分段的方式,对各个馏分段的碱性氮含量和总硫含量进行测试分析。结果表明,在FCC柴油中,总硫含量随着沸点的升高而升高,但碱性氮含量却随着沸点的升高而降低;以直馏柴油作对照实验,结果表明,在直馏柴油中,碱性氮和总硫含量都随沸点的升高而升高。在FCC柴油0％～60％（体积分数）的轻馏分段中集中了78．6％～86．9％的碱性氮,而在60％～100％（体积分数）的重馏分段中集中了49％～56％的硫化物。在FCC柴油中碱性氮主要集中在轻馏分,硫化物主要集中在重馏分。     

启动压力对低渗透油藏无因次采油采液指数的影响及应用研究

建立考虑启动压力的低渗透数学模型,计算出无因次采油采液指数和含水率关系曲线,应用于实际区块中,分析其开发效果。结果表明:低渗透油藏考虑启动压力采液指数,甚至部分低渗透油藏在中高含水期(含水大于50%)具有一定的提液潜力。低渗透油藏无因次采液指数分为两类:第一类无因次采液指数随含水率的上升而递减,在含水率超过40%后变得平缓;第二类无因次采液指数随含水率的上升先减小而后又略有增大。     

油井水泥降失水剂AS的合成与性能评价

采用自由基聚合法,以2-丙烯酰胺基-2- 甲基丙磺酸(AMPS)和丙烯酰胺(AM)为原料合成共聚物,再与木质素磺酸钠复配,合成了降失水剂 AS.通过正交试验优选合成条件,并对降失水剂AS进行了全面的性能评价.评价结果表明:降失水剂AS具有较好的耐热性和耐盐性,在150℃下,降失水剂AS在饱和盐水中的API滤失量(API...