Three‐dimensional numerical simulations of smooth,asymmetrically roughened,and baffled culverts for upstream passage of small‐bodied fish

Traditional box culvert designs lead to development of high velocity zones in the culvert barrel that often impede upstream migration of fish. Herein, three‐dimensional Reynolds‐averaged Navier‐Stokes (RANS)‐ and Large eddy simulation (LES)‐based computational fluid dynamics (CFDs) simulations were performed to compare the effectiveness of smooth, asymmetrically roughened, and corner‐baffled barrels, in creating low‐velocity zones (LVZs) and providing opportunity for upstream passage of small‐bodied fish. The results revealed distinctive benefits provided by the asymmetrically roughened and corner‐baffled barrels relative to the smooth barrel. Cross‐sectional asymmetry, corners, and obstructions are important factors that contribute to the generation of LVZs conducive to fish passage, albeit contiguity of LVZs is required, particularly for weak swimmers. The study demonstrates the adequacy and effectiveness of CFD models to complement traditional laboratory studies in understanding basic mechanisms beneficial to fish passage and to provide insights into future designs.     

齐大山铁矿南帮含水构造带探测研究

为解决采空区突发涌水给矿山安全生产带来的安全威胁,以齐大山铁矿为研究对象,以高密度电阻率法含水构造带理论模型的正演模拟研究为基础,运用高密度电阻率法对采场南帮含水构造带的异常范围进行了圈定;运用瞬变电磁法进行了二次探测,并对高密度电阻率法所圈定的异常范围进行了验证。研究表明:含水构造带显示为低阻异常特征,在高密度电阻率法探测成果图中显示的两处低阻异常与含水构造带理论模型的正演模拟结果一致;同时,在瞬变电磁法探测成果图中显示的低阻区域均在高密度电阻率法所圈定的低阻异常范围内,二者相互验证,这两处低阻异常均为含水构造带的地球物理异常特征的显示,表明采用高密度电阻率法和瞬变电磁法组合识别技术可实现对隐伏含水构造带的先导性探测。     

基于目标级联技术的含风电互联电网机组组合策略

针对含风电互联电网日前安全约束机组组合的规模大、约束复杂、求解困难等问题,提出基于目标级联分析技术的分散协调优化策略。将问题分解为负责区域间边界节点电压相角协调的上层优化问题和以并行方式独立优化各区域发电计划的下层优化问题。下层优化以弃风电量期望和电量不足期望,量化各区域内风电、负荷预测误差,以及常规机组强迫停运等系统运行不确定性所带来的风险,并以罚函数的形式引入目标函数,以综合优化系统可靠性与经济性。2区域12节点系统和IEEE RTS96三区域互联系统算例仿真验证所建模型和算法的有效性。     

Environmental economic dispatch in multi-area power system employing improved differential evolution with fuzzy selection

In a deregulated multi-area electrical power system the objective is to determine the most economical generation dispatch strategy that could satisfy the area load demands, the tie-line limits and other operating constraints. Usually, economic dispatch (ED) deals only with the cost minimization, but minimization of emission content has also become an equally important concern due to the mandatory requirement of pollution reduction for environmental protection. Environmental economic dispatch (EED) is a complex multi-objective optimization (MOO) problem with conflicting goals. Normally a fuzzy ranking is employed to rank the large number of Pareto solutions obtained after solving a MOO problem. But in this paper the preference of the decision maker (DM) is used to guide the search and to select the population for the next generation. An improved differential evolution (DE) method is proposed where the selection operation is modified to reduce the complexity of multi-attribute decision making with the help of a fuzzy framework. Solutions are assigned a fuzzy rank on the basis of their level of satisfaction for different objectives before the population selection and then the fuzzy rank is used to select and pass on better solutions to the next generation. A well distributed Pareto-front is obtained which presents a large number of alternate trade-off solutions for the power system operator. A momentum operation is also included to prevent stagnation and to create Pareto diversity. Studies are carried out on three test cases and results obtained are found to be better than some previous literature.     

重复采动覆岩裂隙率空间分布相似模拟研究——以陕北矿区为例

由于水资源短缺,陕北矿区利用采空区储存矿井水进行再利用,采空区储水量与采动裂隙空间分布密切相关,为准确预测采空区储水量,基于工作面上覆岩层断裂分带划分结果,确定煤矿地下水库的主要储水空间为垮落带与断裂带的裂隙空间,建立了采动覆岩裂隙率空间分布的计算方法,采用相似模拟试验得出了柠条塔矿1^-2煤和2^-2煤重复采动后上覆岩层的下沉曲线,计算出重复采动覆岩裂隙率在垂直和水平方向的空间分布情况。结果表明:沿垂直方向,随着高度增加,覆岩裂隙率逐渐减小,1^-2煤开采后岩层裂隙率由1.87%逐渐下降为1.18%,2^-2煤开采后,裂隙率由12.85%下降为4.11%;沿水平方向,垮落带、断裂带和弯曲下沉带的裂隙率在采空区边缘附近都会产生2个峰值,并且峰值位置逐渐向采空区中央移动,1^-2煤开采后,中间压实区的最大裂隙率为1.21%,两边离层区的最大裂隙率为2.19%,2^-2煤开采后,压实区和离层区最大裂隙率分别为16.1%和6.54%;重复开采后,上覆岩层的裂隙率显著增加,有...     

浅埋深高瓦斯工作面瓦斯抽放对采空区自燃“三带”的影响研究

以五虎山煤矿010908工作面为背景,采用理论分析、数值模拟和现场实测等手段对浅埋深高瓦斯工作面瓦斯抽放对采空区自燃"三带"影响进行研究。研究结果表明:当瓦斯绝对涌出量与采空区漏风量处于均衡状态时,此时瓦斯对煤自燃将出现明显的耦合影响;当采空区漏风量小于瓦斯绝对涌出量时,采空区遗煤自燃将受到阻碍;与之相反,当漏风量大于瓦斯涌出量时,采空区遗煤自燃受瓦斯涌出量的影响较小;高位钻孔与工作面距离越远,采空区内部的漏风路径也越长,采空区氧化带、窒息带所处的区域越向采空区深部扩大,但靠近工作面一侧的氧化带范围并没有出现明显变化。     

干旱矿区采动顶板导水裂隙的演化规律及保水采煤意义

随着我国煤炭资源开发重心的逐步西移,西部地区目前已成为我国煤炭的主产区。总体上,我国西部矿区降雨稀少、蒸发强烈,形成了该区极度干旱缺水、生态环境脆弱的基本特征。以新疆哈密煤田大南湖矿区为例,针对该区侏罗系含煤地层具有成岩时间晚、物理力学强度低、遇水易泥化崩解等特征,采用相似材料模拟、数值模拟等手段,结合邻矿现场实测对比,全面研究了该区顶板采动导水裂隙的发育与演化过程、发育高度与形态特征、渗透性演化规律以及在该区进行水资源保护性开采(保水采煤)的可行性。研究结果表明:研究区侏罗系含煤地层采动导水裂隙的发育裂采比一般在13.09～15.67,整体形态呈"梯台型"特征;采动影响范围内裂隙发育、演化以及渗透系数的演化均呈现"稳定增加-波动变化-恢复稳定"变化特征,导高影响范围内含水层的渗透系数明显增大,一般达到3～5倍;研究区主采煤层顶板具有"多含水结构下的高位隔水层"结构特征,具备了保水的基本水文地质前提条件;结合保护层的稳定性、III-1上段含水层的静储量、开发潜力以及在研究区进行保水采煤可行性的综合评价,探讨了在干旱矿区水资源保护性开采的重要意义。     

大水矿山导水通道及帷幕薄弱带可视化研究

大水矿山主要通过构筑阻水帷幕进行水害治理,由于地质条件的复杂性和技术水平的制约,帷幕构筑时极易形成薄弱带,从而导致帷幕堵水效果较差。本文以恒辉铁矿区为例,在对矿床构造、地层、岩性、水位、注浆情况以及物探资料进行综合研究的基础上,确定了该矿床帷幕薄弱带主要发育在帷幕东北、东南及南部一带。同时借助3DMine软件建立了矿区三维水文地质模型,全方位、可视化地展示了导水通道及帷幕薄弱带与矿体、巷道等的位置关系。研究成果可辅助矿山对巷道及帷幕进行优化设计,为矿山安全生产及灾害预防提供依据。     

开发区的规划设计

本文通过国内开发区的规划设计的实例，分析了区域规划、基础设施的特点，提出了开发区规划设计要点。     

Temporal trend and source apportionment of water pollution in different functional zones of Qiantang River, China

The increasingly serious river water pollution in developing countries poses great threat to environmental health and human welfare. The assignment of river function to specific uses, known as zoning, is a useful tool to reveal variations of water environmental adaptability to human impact. Therefore, characterizing the temporal trend and identifying responsible pollution sources in different functional zones could greatly improve our knowledge about human impacts on the river water environment. The aim of this study is to obtain a deeper understanding of temporal trends and sources of water pollution in different functional zones with a case study of the Qiantang River, China. Measurement data were obtained and pretreated for 13 variables from 41 monitoring sites in four categories of functional zones during the period 1996-2004. An exploratory approach, which combines smoothing and non-parametric statistical tests, was applied to characterize trends of four significant parameters (permanganate index, ammonia nitrogen, total cadmium and fluoride) accounting for differences among different functional zones identified by discriminant analysis. Aided by GIS, yearly pollution index (PI) for each monitoring site was further mapped to compare the within-group variations in temporal dynamics for different functional zones. Rotated principal component analysis and receptor model (absolute principle component score-multiple linear regression, APCS-MLR) revealed that potential pollution sources and their corresponding contributions varied among the four functional zones. Variations of APCS values for each site of one functional zone as well as their annual average values highlighted the uncertainties associated with cross space-time effects in source apportionment. All these results reinforce the notion that the concept of zoning should be taken seriously in water pollution control. Being applicable to other rivers, the framework of management-oriented source apportionment is thus believed to have potentials to offer new insights into water management and advance the source apportionment framework as an operational basis for national and local governments.