南水北调中线冬季水温分布规律数值模拟研究

Numerical simulation study on winter water temperature distribution law in the mid-route of South-to-North Water Transfer Project

水温是南水北调中线冬季输水冰情预报的重要指标之一。以中线工程总干渠冬季水温为研究对象建立一维水温数学模型,模拟不同气象冷暖冬条件与不同输水流量方案下总干渠沿线水温变化过程,揭示水温沿线时空分布规律,并在此基础上给出相关冬季输水调度运行建议。结果表明:总干渠沿线自南向北各闸站水温沿程降低,大部分工况显示冬季水温整体呈现出先下降后缓慢上升的趋势。同一气象条件下,输水流量越大,沿线水温降幅就越小,如在2013年冷冬典型年份下,陶岔渠首输水流量150 m^(3)/s时沿程降温率为0.37℃/100 km,陶岔输水流量350 m^(3)/s时沿程降温率为0.16℃/100 km。同一输水流量条件下,虽然气温升高对水温的提高有一定的效果,但是不同典型冬季年份降温率并没有显著相关性。建议在做好基于中短期寒潮预报的冬季输水实时调控模式研究的前提下,冬季可采取加大流速输水方案(即大流量、低水位输水),减少水温降幅,旨在提升全线非冰盖输水的可行性。

Water temperature is one of the important indicators for the winter water and ice conditions forecast on the mid-route of the South-to-North Water Transfer Project.Taking the winter water temperature of the main canal of the mid-line project as the research object,a one-dimensional water temperature mathematical model is established to simulate the change of water temperature along the main canal under different weather conditions and different water delivery flow schemes,,reveal the temporal and spatial distribution of water temperature along the line,and give correlations on this basis suggestions for water delivery scheduling operation in winter.The results show that the water temperature of the gate stations along the main canal decreases from south to north,and most of the working conditions show that the water temperature in winter shows a trend of first decline and then slowly rise.Under the same weather conditions,the greater the water flow,the smaller the decrease in water temperature along the line.For example,in a typical cold winter in 2013,the temperature reduction rate along the Taocha canal was 0.37℃/100 km when the water flow rate was 150 m^(3)/s,and the temperature reduction rate was 0.16℃/100 km when the Taocha water flow rate was 350 m^(3)/s.Under the same water flow conditions,although the temperature increase has a certain effect on the increase of the water temperature,there is no significant correlation between the cooling rates of different typical winter years.Under the premise of doing a good job in the real-time control mode of water delivery in winter based on medium and short-term cold wave forecasts,it is recommended to adopt an increased flow rate water delivery plan(that is,large flow,low water level water delivery)in winter to reduce the drop in water temperature,to improve the feasibility of non-ice cap water delivery across the line.