西北寒旱区高坝水库的水温与冰情研究

为探究西部寒旱地区水库修建对水温、冰情的影响,采用垂向一维水温冰情模型及纵向一维水温模型,对黑河黄藏寺水库库区和坝下游河道水温、冰情进行了预测,并与建库前进行了对比和分析。研究结果表明:黄藏寺水库水温结构为分层型,冬季坝前水温呈逆温分布,水库的修建对库区及坝下河段冰情程度有一定的弱化,初冰时间较建库前推迟约1个月,冰情持续时间减少约20天,最大冰厚由建库前的0.76 m减小至0.49 m,坝下一定范围内不再有冰情出现;水库泄水出现了一定的春夏季低温水及秋冬季高温水现象,沿程水温在各时段均出现了不同程度的恢复效应。     

基于温度滞后相位的输电线路覆冰监测方法

为获得更加符合实际环境温度下的光纤复合相线温度变化特征、覆冰与否的判据及覆冰厚度预测方法,文中建立环境温度呈正弦函数变化情况下光纤复合相线覆冰的温度场三维模型,并采用有限元方法进行求解。文中分析导线覆冰段与未覆冰段温度变化的幅值和滞后相位特征;研究滞后相位与环境温度波动幅值、滞后相位与覆冰厚度的关系,发现环境温度波动幅值对滞后相位的影响可以忽略;提出基于滞后相位特征的线路覆冰判据,并给出基于滞后相位的覆冰厚度预测公式。文中建模分析获得4种非正弦函数形式的环境温度变化下光纤温度的变化情况,基于此分析覆冰厚度的预测公式误差,仿真结果证明所提出基于滞后相位的覆冰判据和覆冰厚度预测公式的有效性。     

达坂山导线覆冰与气象条件的关系

文章通过计算达坂山区导线覆冰的冰厚、覆冰密度、标准冰厚及其与气象要素相关的系数,分析了导线覆冰随方位、风向等的变化规律,以及达坂山区导线覆冰与气象条件的关系,并提出了合理的预防达坂山导线冰害的措施。     

大型城市湖泊群引水调度模式研究

武汉东湖是国内最大的城中湖,东湖、沙湖、严西湖和北湖组成了大型城市湖泊群。＂大东湖生态水网构建工程＂将重建长江与湖泊群的水力联系,通过引江济湖改善湖泊群的水生态系统。为确定工程合理的引水调度模式,本文建立了湖泊群水动力水质模型,采用正交规则网格,考虑污染物的自然降解和底泥释放,采用零厚度隔板模拟湖中的隔堤,并对模型进行了率定和验证。综合考虑可引长江水量和入湖径流总量,选取典型平水年,对三种引江济湖调度模式进行了深入研究,通过建立的水动力水质模型的动态模拟计算,分析与比较各种调度模式的引水效果,为大东湖生态水网连通工程的实施提供科学的决策依据。     

基于人工神经网络模拟弯槽段水内冰冰塞厚度分布

寒冷地区河流冬季常因冰塞问题而成灾,因此对冰塞所涉及的相关问题进行预测和预报对于防灾减灾具有重要的意义。稳封期的平衡冰塞厚度无论对于上游水位的升高还是对后期的开河均具有直接的和重要的影响,用分析型或确定型模型描述非常复杂的河冰过程所导致的冰塞厚度有相当的困难,因此冰塞体厚度描述较多采用的是经验公式,且基本为断面平均厚度。基于人工神经网络的非线形映射特征,尝试将其用于实验室中弯槽段的冰塞厚度分布预测,对数值结果的计算表明,在实际工程中可以采用该方法进行模拟预测。     

Study of Cycling Air-Cooling System with a Cold Accumulator for Micro Gas-Turbine Installations

Using the cycling air-cooling systems of the CTIC type (Combustion Turbine Inlet Cooling) with a cold accumulator in a micro gas-turbine installation (micro-GTI) to preserve its capacity under the seasonal temperature rise of outside air is described. Water ice is used as the body-storage in the accumulators, and ice water (water at 0.5–1.0°C) is used as the body that cools air. The ice water circulates between the accumulator and the air-water heat exchanger. The cold accumulator model with renewable ice resources is considered. The model contains the heat-exchanging tube lattice-evaporator covered with ice. The lattice is cross-flowed with water. The criterion heat exchange equation that describes the process in the cold accumulator under consideration is presented. The calculations of duration of its active operation were performed. The dependence of cold accumulator service life on water circulation rate was evaluated. The adequacy of the design model was confirmed experimentally in the mock-up of the cold accumulator with a refrigerating machine periodically creating a 200 kg ice reserve in the reservoir-storage. The design model makes it possible to determine the weight of ice reserve of the discharged cold accumulator for cooling the cycle air in the operation of a C-30 type micro- GTI produced by the Capstone Company or micro-GTIs of other capacities. Recommendations for increasing the working capacity of cold accumulators of CTIC-systems of a micro-GTI were made.     

黄河(内蒙古段)弯道卡冰过程及数值模拟研究

野外观测发现天然河流弯道处是封河期最易形成卡冰结坝的位置,冰坝的形成会壅高上游水位,严重时发生凌洪灾害。因此,研究弯道处卡冰过程,分析卡冰结坝机理是河冰研究的关键问题之一。本文中,通过对2013—2014年冬季不同形态弯道河冰过程的野外观测,分析了各种形态弯道卡冰结坝的过程、特性。基于二维Dyna RICE河冰动力学模型对三湖河道弯道表面冰输移进行模拟。结果表明弯道卡冰位置常发生在弯道出口河面束窄处,弯道处上游流凌密度、上游及下游的水力条件和河道形态是影响弯道卡冰结坝的关键因素。本研究对于确定冰坝初始形成位置,为进一步提出防凌减灾措施提供技术支持。     

输电线路覆冰原因分析及优化研究

输电线路覆冰事故频频发生,对电力的安全生产造成很大影响。分析输电线路覆冰的形成机理及影响因素,指出了混合冻结对输电线路危害最为严重,气象、高度、线路、电场均是影响线路覆冰的因素。建立输电线路覆冰厚度的计算模型,通过对弧垂的受力分析得出了一种计算冰层厚度的算法。提出了输电线路除冰方法和预防结冰的措施,指出了采用合理的抗冰设计是防止输电线路覆冰的最有效措施,并对不同除冰方法进行了技术经济分析,为电网的安全运行和改造工作提供了理论基础。     

2001—2014年阿克苏河流域山区积雪时空变化分析

Mountain snow is one of the main water source for the Aksu River in Xinjiang. A comprehensive analysis of spatio-temporal variations in the mountain snow in the Aksu River basin can provide a basic support for runoff analysis. In this paper, the snow products of Moderate Resolution Imaging Spectroradiometer (MODIS) during the period of 2001-2014 were used to analyze the snow cover area and its spatio-temporal variations in the Aksu River basin. Results show that in this period of 14 years, the snow cover area took a decreasing trend in the annual, seasonal and monthly scales, with particularly significant decreasing in the annual maximum snow cover and the snow cover in summer. The major significant changes of snow cover occurred in Tuoshigan River mountainou area, mountainous border region and the west of Kumalake River mountain area in the winter and summer, and significant reduction in permanent snow area occurred in the east of Kumalake River mountain area. Without considering other meteorological factors, temperature rising could be a major cause for reduction in the snow cover.