寒区长距离输水渠道水流冻结模型试验研究

Model Test Research on Freezing Flow of Long-distance Channels in Cold Regions

研究寒区渠道内水流冻结规律对于渠道冰冻灾害防治有积极意义,研制了寒区长距离输水渠道水流冻结模型试验系统,模拟了渠道中冰塞、冰盖的形成过程,分析了水流结冰变化规律及冰盖形成前后水位和流速的变化规律;利用COMSOL Multiphysics软件三维仿真了模型内水流的流态,并与实测流速结果进行对比。结果表明,研制的模型试验系统可较真实地模拟长距离输水渠道冬季运行的实际状态,是研究渠道冬季运行的有效试验手段;冰盖的形成起源于冰花、碎冰在水中障碍物或流速缓慢区域的堆积和热增长;冰盖形成的时间与流速成线性关系;冰盖形成后渠道过水断面各个位置流速普遍减低。

The freezing law of water flow in channels of cold regions was studied through model tests to provide theoretical support for the prevention and control of channel freezing disasters.A water flow freezing model test system for long-distance water conveyance channels in cold regions was developed,which simulated the formation process of ice plugs and ice caps in channels,and analyzed the change law of water freezing,as well as the changes of water level and velocity before and after the formation of ice caps.The COMSOL multiphysics software was used to simulate the flow pattern in the model,and the results were compared with the measured velocity.The results show that the developed model test system can more realistically simulate the actual state of long-distance water conveyance channels in winter,and it is an effective test method for studying the channel operation in winter.The formation of ice cap originates from the accumulation and thermal growth of frazil ices and crushed ices around obstacles or in slow-flow areas.The time of ice cap formation is linearly related to the flow velocity.After the ice cap was formed,the flow velocity generally decreases at various locations across the water section of the channel.