高寒区引水式电站冬季运行抽水融冰机理及运行参数优化研究

Pumping well water to melt ice is a ideal method to solve ice damage of winter operation for diversion-type hydropower station in high altitude and cold regions. But the existed research is limited in technical experience and preliminary application, and it does not reflect the comprehensive influence on hydraulic, thermal ,climatic and other factors.Through theoretical analyses and ice-melting flume experiments, this project will study the distribution law of water temperature, ice density and ice-water velocity along the direction of flow, including water temperature of typical sections.By analyzing on the coupling relationship between water temperature, ice density, ice-water velocity and ice-melting, the ice-melting mechanisms can be discovered.Through comprehensive analyses on the law of ice-free length influenced by hydraulic, thermal and climatic factors, the quantitative relationship between them can be established. Using FLUENT software, the process of pumping well water to melt ice and parameter changes of flow field will be simulated numerically.Combined with flume experiment results, the optimization parameters of single well operation are explored. Based on numerical simulation on the temperature changes process of multi-well operation, and combined with the prototype observation experiment of HongShan Zui hydropower station in Manas River,the optimization parameters of multi-well operation, with different hydraulic, thermal and climatic conditions, are groped ultimately, which can provide scientific basis to solve ice damage of winter operation for diversion-type hydropower station in high altitude and cold regions.

在高寒地区，抽水融冰是解决引水式电站冬季运行冰害的理想措施。但现有研究结果仅局限于对该技术的经验总结和初步应用，不能综合反映水力、热力、气候等多种因素对抽水融冰影响效果，因此本项目拟通过理论分析和融冰水槽试验，研究抽水融冰过程中沿程水温和典型断面水温变化规律、冰花密度沿程分布规律和冰水合流速沿程分布规律，分析水温、冰花密度以及冰水合流速与冰花消融耦合关系，揭示抽水融冰机理；综合分析水力、热力和气候条件对不冻长度影响规律，建立单井不冻长度与各影响因素之间定量关系式；运用FLUENT软件模拟单井抽水融冰过程及流场参数变化，并结合水槽试验结果，探求抽水融冰单井运行优化参数；通过井群运行引水渠沿程水温变化过程模拟研究，并结合新疆玛纳斯河红山嘴电站抽水融冰原型观测试验，最终探索出高寒地区不同水力、热力、气候条件下抽水融冰井群运行优化参数，为解决高寒区引水式电站冬季运行冰害提供科学依据。

本项目以新疆玛纳斯河流域红山嘴电站引水渠道抽水融冰为研究对象，采用原型观测、概化水槽试验和理论分析相结合的方法，开展了抽水融冰机理及运行参数优化的研究。首先对抽水融冰沿程水温变化过程进行了原型观测和概化水槽试验，对抽水融冰运行过程的气候、水力和热力条件进行了全面观测，分析了引水渠道水温、冰花密度和冰水合流速等的沿程变化规律，并结合试验结果对渠道冰害产生的原因和抽水融冰运行机理进行了理论分析；同时，根据水流热平衡理论，建立了不冻长度的计算公式，分别计算了不同水力、热力、气候条件下的不冻长度值，获得了水力、热力和气候条件对冰花消融的影响规律；然后，采用与实际工程一致的边界条件，以红山嘴电站为例，选取最具代表性的5#井前后断面建立引水渠3D模型，对不同条件下的抽水融冰过程进行了数值模拟，验证了抽水融冰效果，给出了渠水和井水混合后水温变化基本规律；最后，选取二级引水渠道的9#、10#、11#井上下游渠段建立引水渠三维紊流数学模型，分别模拟了不同引水流量和大气温度工况下水温的沿程变化，分析了多井联合运行过程中水温沿程变化以及各井之间的耦合影响作用，给出了不同引水流量和不同大气温度条件下不冻长度计算结果和井群的合理布置间距，建立了不同气候、水力、热力条件下抽水融冰井群运行优化参数方案。本项目取得的研究成果不仅能为高寒区引水式电站冬季运行冰害防治提供技术支持，而且也为冰水力学中冰融化问题的研究给予一定补充。