封冻期渠系运行方式

Operation mode of canal system in freezing period

为研究系运行方式与冰塞二者之间的关系,以流速、傅汝德数、水位偏差等参数作为指标,在常规运行方式选择方面,认为上游常水位运行造成的冰塞风险最小,下游常水位运行在封冻时闸门调控及时,等体积运行方式中庸;封冻渠池在封冻时,该渠池运行方式由下游常水位切换为等体积,造成渠系的水位偏差、水力响应过程中的最大流速与傅汝德数等指标均较始终保持下游常水位小,模拟工况下的上游水位偏差减小近50%,最大流速降低约6.5%,表明运行方式切换更有利于维持渠系在封冻时的稳定和减小冰塞风险。因此,推荐封冻渠池在封冻时由下游常水位切换至等体积运行。

In order to study the relationship between the operation mode of the system and the ice jam,the parameters such as flow rate,Froude number,and water level deviation are taken as indexes.In terms of the selection of conventional operation mode,it is considered that the risk of ice jam caused by the operation of the upstream constant water level is the least,the adjustment and control of the gate during the operation of the downstream constant water level is timely,and the equal volume operation mode is moderate.When the frozen canal pool is frozen,the operation mode of the canal pool is changed from the downstream constant water level to the equal volume,resulting in the water level deviation of the canal system.The maximum velocity and the Froude number in the hydraulic response process are smaller than those in the downstream constant water level.The water level deviation in the upstream under simulated conditions decreases by nearly 50%and the maximum velocity decreases by approximately 6.5%,respectively.This indicates that switching operation mode is more conducive to maintaining the stability of the canal system during freezing and reducing the risk of an ice jam.Therefore,it is recommended that the frozen canal pool be switched from the downstream constant water level to the equal volume operation during the frozen period.