Operation simulation model for middle route of south-to-north water transfer project during ice period

The middle route of south-to-north water transfer project is a canal system. The downstream part from Anyang to Beijing has ice in winter every year. And the water resources requirement of this part is still hard in winter. . Ice condition is important to operation the canal system in winter. Ice evolution simulation is an important method to improve ice hazard threat of the middle route of south-to-north water transfer project by ice prediction and canal system automation operation. In this paper, a one dimensional operation simulation model for the middle route of South-to-North water transfer project has been established, which including unsteady flow simulation, water temperature simulation, ice cover evolution simulation and PI controller. It could describe the ice evolution process, hydraulic responses and gates operation process. And the model had taken the canal system characteristics into consideration including ice cannot flow through downstream gate of each pool and coupling of system hydraulic response. Ice observation is a dangerous work, and the project is so long. So, just limited ice observed data at some canal pools of the project is used to confirm the parameters value for the model. The parameters calibration results showed that the heat exchange coefficient of open channel was 18 W/(m2•℃) and heat exchange coefficient under ice sheet conditions was 26 W/(m2•℃), and the averaged error of ice cover thickness and water temperature were 0.67 cm and 0.07 ℃ respectively. So the reliability of the model was confirmed to calibrate water temperature process, ice cover formation process and ice cover thickness process. And then, the model was applied to Beijing-Shijiazhuang part of the south-to-north water transfer project case simulation to study the ice situation evolution, hydraulic response and gate group regulation process in Ianuary-February 2016. The simulated canal system consists of 13 channels separated by 14 control gates. Water transfer flow of Hebei terminal and Tianjin were set as 20 m3/s and 10 m3/s. Two working conditions were simulated according to the temperature conditions. The results showed that the ice evolution parameters value can worked well to simulate ice evolution for long distance canal system, but the air temperature input conditions of the model must be the local value near each pool. The applied case results show that the canal system hydraulic response processes are complicated caused by ice evolution process, and the PI controller can reduce water level fluctuant amplitude and keep on the downstream water level operation mode well. The prediction of ice evolution process and gates operation processes was helpful to improve safety and economic benefit of the engineering.