Advanced Materials Research Vols. 838-841

Abstract: The unique hydraulic characteristics in oxidation ditch have a close relation with the quality of treated water, the design and optimization of the oxidation ditch. The experimentally validated numerical tools, based on computational fluid dynamics(CFD), were proposed. Sewage- sludge two-phase model and liquid-gas two-phase model of an oxidation ditch were built through CFD numerical method. Meanwhile, a velocity field measurement was enforced on the ditch by Acoustic Doppler Velocimeter(ADV). The simulated results and experimental data were in good correspondence, which verify the simulation methods are reasonable and the simulation results are acceptable. The combination of simulation and experimrntal measurement has profound influence on the hydraulic optimization of oxidation ditch. 3D simulation could be a good supplement for improving the hydrodynamic performance in oxidation ditch designs.

Abstract: Earth pressure field and hydrostatic water pressure field are usually considered for classical earth pressure theories. Nonconsideration of groundwater seepage field is one of the main reasons why measured values of water-earth pressure on supporting structures are generally very different from those calculated values.Under the action of seepage,seepage force changes soil effective stress and affects soil shear strength.Through calculating the interraction of the hindering force field and seepage force field,a multi-field coupling problem is solved, a new calculation expressions on the foundation pit is presented.Key words : multi-field coupling; seepage ; lateral pressure ; water-earth pressure ; hindering force

Abstract: In some textbooks, the Steady-flow Integral Method (SIM) was used to compute the full time of Draining into a Ship Lock, although this method is simple, it only provides a coarse estimation and somehow misleads the students due to approximating the unsteady problem as a steady one and ignoring the inertia effect. The more complex CFD-based model, FLUENT, was used to compensate these shortcomings, the Volume of Fluid (VOF) method was utilized to calculate the free-surface, and the turbulence closure was obtained by the realizable k-ε turbulence model. The values of draining time derived from the two different methods have the same order of magnitude. By CFD, a more precise estimation of the draining time and abundant details about the draining process were obtained. In practical engineering, the geometry of a lock is far more complex than here, the SIM is hard to satisfy the demands for a optimal design, while the CFD method is a nice choice for this purpose.

Abstract: In order to promote the efficiency of actual hydropower system operation under limited inflow forecast, an Implicit Stochastic Optimization method using Support Vector Machine (SVM) theory is proposed in this paper to derive long-term optimal operating rules. By applying the model to the Jinsha-Yangtze river system which is the largest hydropower base in China, fitting performance of operating rules is explained and evaluated. System simulation results are given and compared to deterministic optimal operation. Power output processes comparison shows that the average annual system power generation in two scenarios are 395TWh and 392TWh, and the overall operation processes are in well accordance with explicable inconsistency, which proves the efficiency of SVM in operating rules derivation for hydropower stations.

Abstract: The typical area in Ningbo of China was chosen to conduct the micro spray irrigation construction, and the related economic benefit was analyzed. Results showed that: 776 000 yuan would be cost to construct the micro spray irrigation project in tobacco fields with the area of 350 mu; after the micro spray irrigation program put into use, the income of the area would increase 218 500 yuan per year; the calculated EIRR was 19.5%, the calculated ENPV was 997 100 yuan, and the calculated EBCR was 1.86, from the economical angle, the project was reasonable and practicable. The results could provide the theoretical and practical basis for the widespread of micro spray irrigation project of tobacco fields.

Abstract: In the oil field development process, oil wells production capacity has been severely affected by clogged wells. There are many ways to relieve clogged wells, due to easy to operate, on the lifting of the blockage formation, the pressure pulse plugging technology has good prospects, but the current theory remains to be further studied, so the pressure pulse plugging process was simulated necessarily. The task to pressure pulses pulse tube plugging device as the research object, the establishment of its three-dimensional structure model to study the internal structure of the chamber, to analyze the impact of the flow field structure size rule. Establish its simplified model two-dimensional flow field, the compiler can achieve the state of motion of the sphere device UDF, application dynamic mesh of the pulse tube through Fluent unsteady flow was simulated. By convection field pressure, velocity and import-sectional physical monitoring equipment installation depth research and analysis, work flow, pressure relief device structure and the formation process of the pressure shocks field were investigated. Reveal the pulse tube working mechanism, and promote understanding of the pressure pulse plugging the nature of technology, optimize the structure of the pulse tube design basis and direction for the pressure pulse plugging technology and its theoretical foundation dynamics simulations.

Abstract: The Tibetan Plateau is one of the best areas for the study because of its geographical location as well as human disturbance. AS one of the largest lakes in the Qinghai-Tibet Plateau, Nam Co Lake seepage underestimated for a long time. By linear regression analysis of hydrological data from 1970-2005, we qualitatively understands the water level operation mechanism. The result shows that the model deviates from 2000, compared with the actual water level. Correlation analysis indicates the Nam Co Lake seepage flow reduces after 2000. The Three Gorges project resulted in the uplift of the downstream water level, which exacerbates the rise of water level of Nam Co Lake. Owing to the non timeliness of underground seepage recharge, water level of downstream lake is difficult to simulate. According to the result and recent research, underground seepage may be a cycle, affecting the water level of all the lakes.

Abstract: For seepage analysis using Composite Element Method(CEM), the drainage holes are treated as “air sub-elements” with high permeability contained in the conventional rock(soil) element, which is called “composite element”. To ensure the validity and correctness of the calculated results, the “permeability coefficient” of drainage holes and transmissibility coefficient of the interface between rock(soil) and drainage holes are studied and some reasonable suggestions are given. To improve the calculation precision and efficiency of CEM, the p-version adaptive method is studied and the corresponding algorithm of upgrade the hierarchical order and accelerating convergence are implemented in the CEM.

Abstract: The water quality of the Jinshan Lake in Zhen Jiang city were evaluated mainly on the basis of forty samples collected from four locations.The purposes of the study were to assess the levels of parameters associated with the demands of the functions of the water body and to compare them with Environmental Quality Standards for Surface Water. Water quality parameters included pH, Temperature, Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (CODMn), permanganate index, Total Nitrogen (TN), Total Phosphorus (TP), and NH3-N were analyzed. These water quality parameters were surveyed in 2012 on a monthly basis.Most of them met the Class Ⅲ level of Environmental Quality Standards for Surface Water excepting the Total Nitrogen and Total Phosphorus.The results show that the phenomenon of eutrophication existed in the the Jinshan Lake in 2012.

Abstract: With the application of RMA2 two-dimensional (2-D) hydrodynamic model of Surface-water Modeling System (SMS), hydrodynamic characteristics of Jinshan Lake in the process of water injection and water exchange were simulated. The model generalized the river channel, divided mesh, chose the parameters, and controlled the boundary conditions with both the flowrate and the water surface elevation. The hydrodynamic simulation results show that: The simulated and measured value of the water level and flow velocity in the calibration section are in good agreement. On the whole, the simulation can truly reflect the hydrodynamic characteristics of Jinshan Lake and then can provide the hydrodynamic foundations for the study on the dam operation with the core of protecting water quality.