高纬度地区渠道无冰盖输水的冰情控制研究

Study on long-distance water transfer channel with thermal insulation cover in winter

中国北方高纬度地区有一些渠道工程,因其建设年代早,受规划之初经济条件限制,未考虑冰期运行,仅在非冰期输水。随着经济发展,目前亟需实现冬季输水。但是受结构上的限制,这些渠道抗冰冻能力差,无法采取冰盖下输水或冰水二相流输水,通过加设保温盖板,防止渠道结冰,既可解决用水矛盾,又可节省工程改造投资,具有巨大的经济效益和社会效益。本研究根据传热学理论对加设保温盖板后的渠道水体失温过程进行理论分析,并在此基础上建立了设置保温盖板的一维渠道冰期输水数学模型,对加设保温盖板的冰期输水过程进行了模拟,分析了保温材料厚度、输水流量、出库水温等对冰期输水的影响,论证渠道冬季加设保温盖板输水的可行性。并提出了切实可行的冬季输水方案。研究成果对于冰期渠道安全输水和渠道改造都有一定的借鉴意义。

In northern China at high latitudes there are some long-distance water transfer channel projects which are mostly planed or built in the last century. Due to the economic conditions at that time, these channel projects were designed without considering for winter time and only transfer water under non-ice condition. However with the development of economy, it is urgent to transfer water in winter in order to al- leviate the shortage of water presently. But constrained by the structure form, the freezing resistance abili- ties of these channels are poor, which are not suitable for transferring water under ice cover. Instead install- ing thermal insulation covers for channels can prevent water from freezing. This method not only can solve the shortage of water in winter, but also can save the engineering transformation investment, which has great economic benefits and social benefits. In this paper the heat loss process of water in channels with thermal insulation covers is analyzed theoretically. Then a one-dimensional ice-hydraulics mathematical mod- el of channel with thermal insulation covers is established and the heat loss process of water is simulated. The influences of insulation cover thickness, flow rate and outflow temperature from water source on water transfer in winter are analyzed. Finally, on the basis of the above researches, the water transfer feasibility is demonstrated for channels with thermal insulation cover in winter and the safe schemes of water transfer are put forward. The study results have some reference value for water transfer safety and engineering trans- formation for channel project in winter.